Read the following passage and mark the letter A, B, C, or D on your answer sheet to indicate the correct answer to each of the questions from 31 to 40.

Sustainable development has become a priority worldwide, as nations work to balance economic growth with environmental preservation. [I] Sustainable practices are critical to ensure that natural resources are conserved for future generations, while also meeting today’s economic needs. [II] Many countries have invested in green technologies to reduce carbon emissions and slow climate change.

[III] However, achieving sustainability involves more than just technology; it requires a collective shift in mindset towards reducing waste, reusing materials, and protecting biodiversity. [IV] According to the United Nations, sustainable development must incorporate social equity, economic progress, and environmental stewardship to be effective.

A key factor driving sustainability efforts is the awareness of limited resources. The earth’s resources, such as freshwater, fossil fuels, and fertile land, are finite, and overuse can lead to scarcity. In recent years, many nations have implemented regulations to control the extraction and consumption of resources, aiming to curb excessive demand and reduce environmental impact. For example, many cities have introduced restrictions on single-use plastics and have promoted recycling programs as a means to encourage responsible waste management.

While developing countries may prioritize industrial growth to boost economic development, developed nations often focus on reducing their carbon footprint and promoting eco-friendly policies. This disparity can lead to challenges in international relations, as countries negotiate agreements on emissions and resource use. Organizations like the United Nations work to bridge these gaps through global frameworks that encourage cooperation, but disparities in priorities and resources can hinder progress.

Increasing public awareness about environmental sustainability has been another critical component of these efforts. Through education and media campaigns, individuals are encouraged to adopt environmentally conscious practices, such as reducing energy consumption, using public transport, and supporting local economies. By making small adjustments in daily life, individuals contribute to broader global sustainability goals, ultimately promoting a healthier planet for future generations.

 

Which of the following best paraphrases the underlined sentence in paragraph 3?

Read the following passage and mark the letter A, B, C or D on your answer sheet to indicate the best answer to each of the following questions from 31 to 40.

[I] Green living, often referred to as sustainable living, encourages individuals to adopt environmentally friendly practices in their daily lives. [II] This lifestyle includes reducing waste, conserving natural resources, and promoting eco-friendly habits, which collectively help to minimize the negative impact on the environment (Davies & Mulligan, 2017). [III] Although green living requires effort and adjustment, its benefits for the planet and future generations are substantial. [IV]

One of the fundamental aspects of green living is waste reduction. This can be achieved through practices like recycling, composting, and reducing single-use plastics. According to a report by the Environmental Protection Agency (EPA), recycling and composting can significantly decrease the amount of waste sent to landfills, which helps reduce greenhouse gas emissions and pollution (EPA, 2021). Additionally, adopting reusable items such as water bottles and shopping bags minimizes reliance on plastic, which is crucial for protecting ecosystems and wildlife.

Another key component of green living is energy conservation. Simple changes, like switching to LED light bulbs and using public transportation, can reduce an individual's carbon footprint. A study by the International Energy Agency (IEA) shows that energy efficiency improvements, if widely implemented, could decrease global energy demand by up to 40% by 2050 (IEA, 2019). By conserving energy, individuals not only lower their utility bills but also contribute to the reduction of carbon emissions, which is essential for mitigating climate change.

Green living also involves making conscious choices about the products we consume. This includes opting for sustainably sourced goods, supporting local businesses, and choosing organic produce. Sustainable agriculture practices reduce the need for chemical pesticides and fertilizers, which can harm both the soil and water sources (Smith & Taylor, 2020). By making informed purchases, consumers can support eco-friendly industries and help create a demand for greener alternatives.

Which of the following best summarizes paragraph 3?

Read of the following leaflet and mark the letter A, B, C or D on your answer sheet to indicate the option that best fits each of the numbered blanks from 7 to 12.

Join Our Eco-Friendly Community

If you want to make a difference, join (7)_______community members dedicated to sustainability. Together, we can (8)_______ positive change in our environment. Our community focuses on the importance of (9)_______to reduce waste. Join us in our fight against climate change (10)_______ contribute to a healthier planet.

Participate in our (11)__________that teach sustainable living practices. Our mission is to educate members about the (12)_________of green energy solutions.

Join us today and be part of a movement that matters!

Read the following passage and mark the letter A, B, C or D on your answer sheet to indicate the best answer to each of the following questions from 31 to 40.

In an era of increasing global awareness, debates around sustainable practices such as fair trade, organic farming, and recycling are gaining prominence. Farmers in developing countries are among the most vulnerable people, dependent on world commodity markets, middlemen, and unpredictable weather. 

(I)Fair trade arrangements aim to support cooperative groups by guaranteeing prices above the world market rate and additional bonuses. (II) However, critics argue that fair trade may not lift a country out of poverty. (III)They claim that most of the money generated from sales goes to wealthy countries that promote these products. (IV)In fact, only about 5% of the sale price of a fair-trade chocolate bar (retailing for £1.73 in the UK) reaches the poor country.

Another significant trend is the rise of organic food, marketed as being free of chemicals, which appeals to consumers concerned about the dangers of chemicals in food. These chemicals are suspected of causing various health problems, including cancer and developmental issues in children. Despite these concerns, British farmers have not converted to organic farming in large enough numbers to meet the demand. As a result, supermarkets often import organic vegetables from distant countries, contributing to higher greenhouse gas emissions due to transportation. Environmentalists are now urging consumers to buy locally grown vegetables, even if they are pesticide-treated, suggesting a good wash can minimize the risk.

In recent years, a shift has occurred in how we handle waste. Once content to bury it in landfills or dump it at sea, we are now encouraged to recycle and treat waste as a resource. This shift has led to more widespread kerbside collections for various materials like paper, plastic, and metal. However, recycling has unintended consequences. Most of the UK's recyclables are sent to China or India, which incurs additional environmental costs from transportation. In these countries, workers often sort waste under dangerous conditions. Sometimes, materials that are sorted at home still end up in landfills because the market for them fluctuates.

While efforts to promote sustainability are commendable, they require constant evaluation to ensure they truly benefit people and the environment, rather than creating new inequalities or environmental harm.

Where in the passage does the following sentence best fit? "This growing fair-trade market has distributed hundreds of millions of pounds to over 50 million people worldwide."

Mark the letter A, B, C, or D on your answer sheet to indicate the best arrangement of utterances or sentences to make a meaningful exchange or text in each of the following questions from 13 to 17.

a. First, we suggest that the school should provide more recycling bins.

b. Third, we recommend that we make use of plastic waste in arts and crafts projects, for example, for making plant pots or bird feeders.

c. Reusing and recycling single-use plastics will lead to a greener school environment and help promote a green lifestyle among young people. Therefore, we recommend you put the suggested solutions into practice as soon as possible.

d. To solve the problem of single-use plastics in our school, we propose the following solutions.

e. Second, the Youth Union should hold regular sessions to teach students how to recycle properly.

Read the following passage about The Benefits of Outdoor Activities and mark the letter A, B, C or D on your answer sheet to indicate the best answer to each of the following questions from 23 to 30.

Engaging in outdoor activities has become increasingly popular in recent years. Not only do these activities provide an escape from the daily grind of life, but they also offer numerous physical and mental health benefits. Hiking, cycling, and team sports are just a few examples of outdoor activities that can enhance well-being.

First and foremost, outdoor activities encourage physical fitness. Regular participation in activities like hiking or cycling helps individuals maintain a healthy weight and improve cardiovascular health. The fresh air and natural surroundings can make exercising feel less like a chore and more like an enjoyable experience. Furthermore, studies have shown that spending time in nature can reduce stress levels and promote a sense of tranquility.

In addition to physical benefits, outdoor activities foster social connections. Participating in team sports or group hikes allows individuals to meet new people and strengthen existing relationships. The shared experience of overcoming challenges together can build camaraderie and enhance teamwork skills.

However, some people might argue that outdoor activities are not accessible to everyone. For instance, individuals living in urban areas may find it difficult to access green spaces or safe paths for cycling. This raises the question of equity in accessing outdoor resources.

Despite these challenges, the advantages of engaging in outdoor activities far outweigh the drawbacks. Those who participate regularly often report feeling happier and more fulfilled. The sense of achievement that comes from completing a challenging hike or mastering a new cycling route can significantly boost self-esteem.

In conclusion, outdoor activities play a crucial role in promoting both physical health and social well-being. By stepping outside and embracing nature, individuals can improve their quality of life. As we continue to navigate the complexities of modern living, it is vital to prioritize these enriching experiences.

Which of the following is NOT mentioned as a benefit outdoor activity?

Read the following leaflet and mark the letter A, B, C or D on your answer sheet to indicate the option that bestfits each of the numbered blanks from 7 to 12.

TO LIVE SUSTAINABLY, START AT HOME!

Let’s discover how we can contribute to a more sustainable lifestyle in our everyday activities.

Facts and figures: In the past decade, (7) _______ people have begun to recognize the importance of sustainability. Yet, we still (8) _______ millions of tons of food waste each year. This not only affects our environment but also contributes to food scarcity.

Positive action!

Use less plastic! Whenever possible, opt for (9) _______ alternatives to plastic products. This small change can make a big difference.

Shop smart! (10) _______ buying unnecessary items, focus on what you really need. This will help decrease waste and save money.

Make the most of resources! Learn to (11) _______ things you might usually throw away. For instance, vegetable scraps can be used for broth.

Involve your community! Encourage (12) _______ to participate in local clean-up events to foster a collective effort for a cleaner environment.

Read the following passage and mark the letter A, B, C or D on your answer sheet to indicate the best answer to each of the following questions from 31 to 40.

In an era of increasing global awareness, debates around sustainable practices such as fair trade, organic farming, and recycling are gaining prominence. Farmers in developing countries are among the most vulnerable people, dependent on world commodity markets, middlemen, and unpredictable weather. 

(I)Fair trade arrangements aim to support cooperative groups by guaranteeing prices above the world market rate and additional bonuses. (II) However, critics argue that fair trade may not lift a country out of poverty. (III)They claim that most of the money generated from sales goes to wealthy countries that promote these products. (IV)In fact, only about 5% of the sale price of a fair-trade chocolate bar (retailing for £1.73 in the UK) reaches the poor country.

Another significant trend is the rise of organic food, marketed as being free of chemicals, which appeals to consumers concerned about the dangers of chemicals in food. These chemicals are suspected of causing various health problems, including cancer and developmental issues in children. Despite these concerns, British farmers have not converted to organic farming in large enough numbers to meet the demand. As a result, supermarkets often import organic vegetables from distant countries, contributing to higher greenhouse gas emissions due to transportation. Environmentalists are now urging consumers to buy locally grown vegetables, even if they are pesticide-treated, suggesting a good wash can minimize the risk.

In recent years, a shift has occurred in how we handle waste. Once content to bury it in landfills or dump it at sea, we are now encouraged to recycle and treat waste as a resource. This shift has led to more widespread kerbside collections for various materials like paper, plastic, and metal. However, recycling has unintended consequences. Most of the UK's recyclables are sent to China or India, which incurs additional environmental costs from transportation. In these countries, workers often sort waste under dangerous conditions. Sometimes, materials that are sorted at home still end up in landfills because the market for them fluctuates.

While efforts to promote sustainability are commendable, they require constant evaluation to ensure they truly benefit people and the environment, rather than creating new inequalities or environmental harm.

According to the passage, which of the following statements is TRUE?

Read the following passage about The Benefits of Outdoor Activities and mark the letter A, B, C or D on your answer sheet to indicate the best answer to each of the following questions from 23 to 30.

Engaging in outdoor activities has become increasingly popular in recent years. Not only do these activities provide an escape from the daily grind of life, but they also offer numerous physical and mental health benefits. Hiking, cycling, and team sports are just a few examples of outdoor activities that can enhance well-being.

First and foremost, outdoor activities encourage physical fitness. Regular participation in activities like hiking or cycling helps individuals maintain a healthy weight and improve cardiovascular health. The fresh air and natural surroundings can make exercising feel less like a chore and more like an enjoyable experience. Furthermore, studies have shown that spending time in nature can reduce stress levels and promote a sense of tranquility.

In addition to physical benefits, outdoor activities foster social connections. Participating in team sports or group hikes allows individuals to meet new people and strengthen existing relationships. The shared experience of overcoming challenges together can build camaraderie and enhance teamwork skills.

However, some people might argue that outdoor activities are not accessible to everyone. For instance, individuals living in urban areas may find it difficult to access green spaces or safe paths for cycling. This raises the question of equity in accessing outdoor resources.

Despite these challenges, the advantages of engaging in outdoor activities far outweigh the drawbacks. Those who participate regularly often report feeling happier and more fulfilled. The sense of achievement that comes from completing a challenging hike or mastering a new cycling route can significantly boost self-esteem.

In conclusion, outdoor activities play a crucial role in promoting both physical health and social well-being. By stepping outside and embracing nature, individuals can improve their quality of life. As we continue to navigate the complexities of modern living, it is vital to prioritize these enriching experiences.

The word “encourage” in paragraph 2 could be best replaced by_________.

Read the following leaflet and mark the letter A, B, C or D on your answer sheet to indicate the option that best fits each of the numbered blanks from 7 to 12.

Are you passionate about the environment? Do you want to inspire (7)______to take action? Join our English Speaking Contest on the theme "Saving the Earth"!

Eligibility:

Open to all high school and university students.

Contest Details:

Participants will deliver a 5-minute speech focusing on how individuals and communities can (8)          harmful activities. The contest encourages creative and impactful ideas to tackle the growing (9)______of pollution and waste harming our planet.

Prizes:

•    First Prize: A trip to an eco-friendly resort, free(10)______, and a trophy.

•    Other winners will receive prizes such as cash awards and gift hampers.

Additional Benefits:

All participants will receive a (11)______of recognition for their efforts in raising awareness about environmental protection.

Key Dates:

•   Registration Deadline: March 1, 2024

•   Contest Date: March 20, 2024

Venue:

Green Future Hall, City Center.

How to Apply:

Register on our website or at the school office.(12)______ you meet the criteria, a confirmation email will be sent with further details.

Let’s speak up and make a difference! Together, we can save the Earth! 

Read the following leaflet and mark the letter A, B, C or D on your answer sheet to indicate the option that best fits each of the numbered blanks from 7 to 12.

Are you passionate about the environment? Do you want to inspire (7)______to take action? Join our English Speaking Contest on the theme "Saving the Earth"!

Eligibility:

Open to all high school and university students.

Contest Details:

Participants will deliver a 5-minute speech focusing on how individuals and communities can (8)          harmful activities. The contest encourages creative and impactful ideas to tackle the growing (9)______of pollution and waste harming our planet.

Prizes:

•    First Prize: A trip to an eco-friendly resort, free(10)______, and a trophy.

•    Other winners will receive prizes such as cash awards and gift hampers.

Additional Benefits:

All participants will receive a (11)______of recognition for their efforts in raising awareness about environmental protection.

Key Dates:

•   Registration Deadline: March 1, 2024

•   Contest Date: March 20, 2024

Venue:

Green Future Hall, City Center.

How to Apply:

Register on our website or at the school office.(12)______ you meet the criteria, a confirmation email will be sent with further details.

Let’s speak up and make a difference! Together, we can save the Earth! 

Read the following passage and mark the letter A, B, C or D on your answer sheet to indicate the best answer to each of the following questions from 31 to 40.

[I] Green living, often referred to as sustainable living, encourages individuals to adopt environmentally friendly practices in their daily lives. [II] This lifestyle includes reducing waste, conserving natural resources, and promoting eco-friendly habits, which collectively help to minimize the negative impact on the environment (Davies & Mulligan, 2017). [III] Although green living requires effort and adjustment, its benefits for the planet and future generations are substantial. [IV]

One of the fundamental aspects of green living is waste reduction. This can be achieved through practices like recycling, composting, and reducing single-use plastics. According to a report by the Environmental Protection Agency (EPA), recycling and composting can significantly decrease the amount of waste sent to landfills, which helps reduce greenhouse gas emissions and pollution (EPA, 2021). Additionally, adopting reusable items such as water bottles and shopping bags minimizes reliance on plastic, which is crucial for protecting ecosystems and wildlife.

Another key component of green living is energy conservation. Simple changes, like switching to LED light bulbs and using public transportation, can reduce an individual's carbon footprint. A study by the International Energy Agency (IEA) shows that energy efficiency improvements, if widely implemented, could decrease global energy demand by up to 40% by 2050 (IEA, 2019). By conserving energy, individuals not only lower their utility bills but also contribute to the reduction of carbon emissions, which is essential for mitigating climate change.

Green living also involves making conscious choices about the products we consume. This includes opting for sustainably sourced goods, supporting local businesses, and choosing organic produce. Sustainable agriculture practices reduce the need for chemical pesticides and fertilizers, which can harm both the soil and water sources (Smith & Taylor, 2020). By making informed purchases, consumers can support eco-friendly industries and help create a demand for greener alternatives.

According to paragraph 2, which of the following is NOT a way to reduce waste?

Read the following passage about the urban shift and mark the letter A, B, C or D on your answer sheet to indicate the best answer to each of the following questions from 31 to 40. 

Pollution and Its Global Impact

[I] Pollution is one of the most pressing issues in the modern world, affecting not only the environment but also public health and global economies. [II] While urbanization and industrialization have brought significant progress, they have also introduced severe environmental challenges. [III] Reducing pollution requires a comprehensive approach that includes public awareness, technological innovation, and stricter environmental policies. [IV]

Air pollution is among the most widespread forms of environmental degradation. It stems from emissions by vehicles, factories, and deforestation, leading to harmful effects on both human health and the climate. According to the United Nations, fine particulate matter (PM2.5) causes millions of premature deaths annually. Water pollution, caused by untreated waste, agricultural runoff, and oil spills, destroys marine ecosystems and threatens human water supplies. Similarly, soil pollution—often overlooked—results from pesticides, heavy metals, and industrial waste, severely impacting agriculture and biodiversity.

While governments worldwide have implemented measures to combat pollution, individual action is equally essential. Reducing plastic consumption, opting for sustainable transportation, and recycling waste can significantly lessen environmental harm. Moreover, industries must adopt cleaner production methods, such as renewable energy and green technology. However, these solutions are effective only when paired with robust educational campaigns that encourage people to understand and address pollution’s consequences.

Despite these efforts, the problem persists, especially in developing nations, where economic constraints hinder environmental policies and waste management systems. At the same time, wealthier countries often export waste to poorer regions, exacerbating the issue. Experts stress that international cooperation is essential to tackle pollution on a global scale. Unless all nations contribute, the planet’s resources and ecosystems may face irreversible damage.

Which of the following can be inferred from the passage?

Read the following passage and mark the letter A, B, C or D on your answer sheet to indicate the best answer to each of the following questions from 31 to 40.

In an era of increasing global awareness, debates around sustainable practices such as fair trade, organic farming, and recycling are gaining prominence. Farmers in developing countries are among the most vulnerable people, dependent on world commodity markets, middlemen, and unpredictable weather. 

(I)Fair trade arrangements aim to support cooperative groups by guaranteeing prices above the world market rate and additional bonuses. (II) However, critics argue that fair trade may not lift a country out of poverty. (III)They claim that most of the money generated from sales goes to wealthy countries that promote these products. (IV)In fact, only about 5% of the sale price of a fair-trade chocolate bar (retailing for £1.73 in the UK) reaches the poor country.

Another significant trend is the rise of organic food, marketed as being free of chemicals, which appeals to consumers concerned about the dangers of chemicals in food. These chemicals are suspected of causing various health problems, including cancer and developmental issues in children. Despite these concerns, British farmers have not converted to organic farming in large enough numbers to meet the demand. As a result, supermarkets often import organic vegetables from distant countries, contributing to higher greenhouse gas emissions due to transportation. Environmentalists are now urging consumers to buy locally grown vegetables, even if they are pesticide-treated, suggesting a good wash can minimize the risk.

In recent years, a shift has occurred in how we handle waste. Once content to bury it in landfills or dump it at sea, we are now encouraged to recycle and treat waste as a resource. This shift has led to more widespread kerbside collections for various materials like paper, plastic, and metal. However, recycling has unintended consequences. Most of the UK's recyclables are sent to China or India, which incurs additional environmental costs from transportation. In these countries, workers often sort waste under dangerous conditions. Sometimes, materials that are sorted at home still end up in landfills because the market for them fluctuates.

While efforts to promote sustainability are commendable, they require constant evaluation to ensure they truly benefit people and the environment, rather than creating new inequalities or environmental harm.

Which of the following is NOT mentioned as a challenge faced by farmers in developing countries?

Read the following passage about endangered languages and mark the letter A, B, C or D on your answer sheet to indicate the best answer to each of the following questions from 23 to 30.

            In an era marked by climate change and environmental degradation, adopting green living habits has become increasingly vital. Green living refers to a lifestyle that seeks to minimize one's ecological footprint through conscious choices in daily activities. This can include everything from reducing waste to conserving energy and using sustainable products. As more individuals recognize the importance of preserving our planet, the movement toward greener practices continues to gain momentum.

            One of the most significant aspects of green living is its focus on sustainability. By choosing products that are eco-friendly, consumers can support businesses that prioritize environmental responsibility. For instance, using reusable bags, bottles, and containers reduces plastic waste and promotes a circular economy. Furthermore, opting for locally sourced foods not only supports local farmers but also decreases the carbon emissions associated with transportation.

            When green living habits are adopted, they can lead to profound changes in our environment. By reducing their energy consumption through the use of energy-efficient appliances, individuals help lower greenhouse gas emissions. Consequently, this contributes to cleaner air and mitigates the effects of climate change. Moreover, by practicing water conservation methods, such as fixing leaks and using low-flow fixtures, households can significantly decrease water waste, promoting the sustainable use of this precious resource.

            In conclusion, educating individuals about green living habits is crucial for promoting a more sustainable future. Schools and community organizations can offer workshops and resources that highlight the benefits of eco-friendly practices. Additionally, social media campaigns can raise awareness and encourage people to share their experiences with sustainable living. By empowering individuals to make informed choices, we can collectively work toward a healthier planet for generations to come.

The word “their” in paragraph 3 refers to _______.

Read the following passage about humanoid robots and mark the letter A, B, C or D on your answer sheet to indicate the option that best fits each of the numbered blanks from 18 to 22.

         The future of electric vehicles (EVs) is promising, as technological advancements and environmental concerns (18) __________. As governments worldwide implement stricter emissions regulations and offer incentives for EV adoption, manufacturers are investing heavily in research and development. (19) __________, resulting in longer ranges and faster charging times.

For instance, new solid-state batteries have the potential to enhance energy density and safety, making EVs more practical for everyday use.

         Additionally, the rise of autonomous driving technology is set to revolutionize the way we interact with vehicles. Many electric models are now equipped with advanced driver-assistance systems (20) __________. Furthermore, the integration of smart technology allows for seamless connectivity, enabling drivers to monitor their vehicle's performance and locate charging stations through mobile apps.

         As charging infrastructure continues to expand, (21) __________, the convenience of owning an EV is increasing. This transition to electric vehicles not only promises a reduction in carbon emissions but also fosters a cleaner, healthier environment. Overall, (22) __________ and sustainable transportation.

Read the following leaflet and mark the letter A, B, C, or D on your answer sheet to indicate the option that best fits each of the numbered blanks from 7 to 12.

VOLUNTEERS FOR GREEN CAMPAIGN

Our club would like to recruit ___(7)___ for our Green Campaign.

Are you ___(8)___ 15 years old? And do you really wish ___(9)___ a difference?

Please volunteer for our Green Lifestyle initiative, ___(10)___ clean up our communities and nurture disadvantaged children.

Make an impact, one action at a time!

Embrace a fulfilling experience that not only cares for the environment but also ___(11)___ the lives of those in need.

Together, let's create a sustainable future and spread kindness.

___(12)___ interested in our campaign, please sign up!

Read the following leaflet and mark the letter A, B, C or D on your answer sheet to indicate the option that bestfits each of the numbered blanks from 7 to 12.

TO LIVE SUSTAINABLY, START AT HOME!

Let’s discover how we can contribute to a more sustainable lifestyle in our everyday activities.

Facts and figures: In the past decade, (7) _______ people have begun to recognize the importance of sustainability. Yet, we still (8) _______ millions of tons of food waste each year. This not only affects our environment but also contributes to food scarcity.

Positive action!

Use less plastic! Whenever possible, opt for (9) _______ alternatives to plastic products. This small change can make a big difference.

Shop smart! (10) _______ buying unnecessary items, focus on what you really need. This will help decrease waste and save money.

Make the most of resources! Learn to (11) _______ things you might usually throw away. For instance, vegetable scraps can be used for broth.

Involve your community! Encourage (12) _______ to participate in local clean-up events to foster a collective effort for a cleaner environment.

Read the following passage about human life expectancy and mark the letter A, B, C or D on your answer sheet to indicate the best answer to each of the following questions from 23 to 30. 

An engine is a machine that creates mechanical motion from energy. In order to do this, an engine frequently requires some type of fuel to burn. Nowadays, many engines are used to power cars and other forms of transportation. These vehicles most commonly have an internal combustion engine and rely upon gasoline for power. However, there are several types of engines that can use alternative energy sources. Many people are trying to switch to them because gasoline, which is a fossil fuel, creates pollution and is also a non-renewable resource.

These days, engines that are able to burn biofuels are somewhat common. Biofuels are fuels that are made from biological material, such as corn, soybeans, and sugarcane. These biofuels burn cleanly, so they produce much less pollution than fossil fuels. In some countries, such as Brazil, cars with biofuel engines are standard. In fact, most of the cars in Brazil have engines that can operate on either gasoline or biofuel.

A second type of alternative engine is the electric engine. Cars with electric engines have been common for decades. Most are being used in hybrid cars at the moment. These are vehicles that have both a gasoline-powered engine and an electric one. In many cases, the gasoline-powered engine is used to operate the car at high speeds on expressways. The electric engine is utilised for city driving. One benefit of hybrid cars is that as the gasoline-powered engine runs, it simultaneously recharges the electric engine.

A third type of alternative engine is the hydrogen engine. It utilises hydrogen fuel cells, which convert hydrogen into electricity that can power the car These days, there are many cars and buses that rely upon hydrogen engines. However, there are some problems associated with this type of engine. The hydrogen used in the engine must be processed from other materials, and it is also difficult to store. As a result, vehicles that run on hydrogen are expensive.

Alternative energy sources create less pollution and are often renewable sources of energy. It is hoped that more and more innovations help the use of alternative energy sources become easier and easier.

Which of the following is not mentioned in the text above as renewable energy?