Read the following passage and choose the best answer to each of the following questions from 31 to 40.

1. Extreme habitats are environments where most life, including humans, cannot survive. [I] These areas can be either very cold or very hot. [II] For example, polar regions are extremely cold, with temperatures often falling below 5°C. [III] Despite these harsh conditions, some microbes are able to live and even thrive in these areas. [IV] These bacteria are a type of psychrophile, which are microorganisms that grow best at temperatures of 15°C or lower.

2. On the other hand, some of the most extreme habitats are hot, with temperatures reaching over 40°C. These places are often near geothermal activity, such as deep-sea vents and hot springs. In 1966, microbiologist Thomas Brock discovered that microorganisms were surviving and growing in the hot springs of Yellowstone National Park. These organisms, known as thermophiles, require high temperatures to live. Deserts are also considered extreme hot environments. For example, the sidewinder snake has adapted to survive in the desert by moving in a way that only parts of its body touch the hot sand, reducing its exposure to the heat.

3. Organisms that survive in these extreme conditions can teach scientists important lessons. One example is the wood frog in Alaska (Lithobates sylvaticus). During winter, these frogs freeze completely, but when spring comes, they thaw and continue their lives. Scientists discovered that the frogs create chemicals that protect their organs from ice damage. This finding can help researchers develop methods to extend the preservation of human organs. Such advancements may be crucial for improving organ transplants.

4. Another remarkable organism is the tardigrade, also known as the water bear. This tiny creature can survive in many extreme environments, such as high mountains, deep oceans, and cold Antarctica. The water bear has even survived in space. By studying these organisms, scientists hope to learn more about life on other planets, such as Mars.

 

The word thaw in paragraph 3 is OPPOSITE in meaning to __________.

Read the following advertisement 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 1 to 6.

ANNOUNCEMENT

The Ho Chi Minh Communist Youth Union is pleased (1)______a field trip for qualified 12th-grade students. This is a wonderful opportunity to explore nature and learn about a (2)______.

Destination: Trang An Scenic Landscape Complex

Date: Saturday, January 20, 2025

Trang An is a mixed heritage site (3)______by UNESCO. It owes its beauty (4)______majestic limestone mountains and a network of unique caves. The area is also known for its stunning natural scenery. With its rich history, it is a destination that’s (5)______ for those who love discovering culture and nature.

The trip will include cave exploration, boat rides, and learning about the region's cultural landscapes. To (6)______a decision about joining, please contact your homeroom teacher to register before January 15.

Let’s plan a field trip filled with meaningful experiences and unforgettable memories!

Mark the letter A, B, C, or D on your answer sheet to indicate the correct answer to each of the  following questions.

The Amazon _________ is home to more than a third of all the world’s species of plans. Birds, and animals.

Read the following passage and choose the best answer to each of the following questions from 31 to 40.

1. [I] All living organisms on Earth need water to survive, but more than 100,000 species, including humans, require a special type of water called fresh water, which is found in limited amounts. [II] Freshwater ecosystems are made up of various plants, animals, microbes, soil, rocks, sunlight, and water that all interact around this valuable resource. [IV] Less than three percent of the Earth's total water is freshwater, and less than half of that is in liquid form. [IV]

2. Freshwater ecosystems naturally share resources between different habitats. For instance, rivers and streams transport salts and nutrients from higher elevations like mountains to lower areas, such as lakes, ponds, and wetlands. Eventually, these nutrients reach the ocean. These waterways also enable migrating species, such as salmon, to carry nutrients from the ocean back to freshwater ecosystems, providing essential support for these habitats upstream.

3. Lakes and ponds also undergo nutrient exchanges through seasonal cycles. Cold water, which is denser than warm water, sinks to the bottom, maintaining a more constant temperature. As winter arrives and the air temperature drops, the surface water becomes colder than the water at the bottom, causing it to sink and push the warmer water up. This process repeats in the spring when the ice melts, bringing nutrients from the lake's bottom to the surface, where they can be utilized by plants and animals.

4. It is normal for ecosystems to encounter change. Temperatures may fluctuate, populations may rise and fall, and rain may bring an abundance of water, then taper during drought. The plants, animals, and microbes in healthy freshwater ecosystems are resilient and have adaptations that allow them to adjust appropriately until ideal conditions resume. However, if any element of the ecosystem varies too far outside of the norm, the balance of the whole system can start to fail.

Which of the following best summarises paragraph 2?

Read the following passage and choose the best answer to each of the following questions from 31 to 40.

1. [I] Invasive species pose a significant threat to ecosystems, wildlife, and human activities. [II] These species can include amphibians like cane toads, plants, insects, fish, fungi, bacteria, or even seeds and eggs that are not native to a specific area. [III] Not all invasive species come from other countries. [IV] For example, lake trout, native to the Great Lakes, are considered invasive in Yellowstone Lake because they compete with native cutthroat trout for habitat and resources.

2. Human activities are the primary way invasive species spread, often unintentionally. Global travel and trade allow species to move quickly across ecosystems. Ships can carry aquatic organisms in their ballast water, while smaller boats transport species on their propellers. Insects can travel in wooden shipping crates or pallets, and ornamental plants may escape into the wild and spread. Released pets, like Burmese pythons in the Everglades, can also become invasive. Additionally, climate change worsens the situation by enabling invasive plants, like kudzu, and pests, like the mountain pine beetle, to expand into new areas.

3. Invasive species harm wildlife in various ways. Without natural predators, they can reproduce quickly and dominate ecosystems. Native animals often lack defenses or cannot compete with these aggressive species, which leads to disruptions in the ecosystem and poses serious challenges for native wildlife.

4. Direct threats from invasive species include preying on native wildlife, spreading diseases, and competing for food and resources. Indirectly, invasive species disrupt ecosystems by reducing biodiversity, destroying native food sources, and altering habitats. For instance, aggressive plants like kudzu can create monocultures, replacing diverse ecosystems. Some invasive species even change soil chemistry or increase wildfire risks. Preventing the spread of invasive species is essential to protect ecosystems and maintain biodiversity.

The word they in paragraph 1 refers to __________.

Mark the letter A, B, C, or D on your answer sheet to indicate the correct answer to each of the following questions.

We should_________ before the wet season.

Mark the letter A, B, C, or D on your answer sheet to indicate the correct option that best fits each of  the numbered blanks from 18 to 23. 

        Hot weather makes the heart (18)_______. That is the reason why the majority of mountain rescue statistics are made up from summer walkers suffering heart attacks. So, how to walk safely in summer?

The answer is to keep up the water intake. It is vital not to wait until a thirst (19) _______ Instead, keep drinking regularly from your water bottle.

Given that evaporation is the body's way to cool  (20)_______, soaking a hat with water is a great way to cool the head. Walking in the heat increases the rate at which your feet swell, (21)_______. Cool water from a stream reduces any swelling and helps general foot comfort.

As for what clothing you wear, this should be lightweight and reasonably loose-fitting. Tight clothing will feel uncomfortable and may even lead to an irritating rash on the skin. The answer, if this does develop, is to try and stay cool as much as possible. Do this by either keeping in the shade, (22)________, but without soap.

It is understandable to want to remove some clothing when it is extremely hot, but it does not really make much sense to take off T-shirts. The sun's rays can be quite strong, and shoulders are always very sensitive to sunburn. This is the worst place to be red and sore when you are wearing a heavy rucksack on your back. Wearing shorts can also create problems for walkers, as the backs of the legs can (23)__________.

Read the following passage and choose the best answer to each of the following questions from 31 to 40.

1. [I] Invasive species pose a significant threat to ecosystems, wildlife, and human activities. [II] These species can include amphibians like cane toads, plants, insects, fish, fungi, bacteria, or even seeds and eggs that are not native to a specific area. [III] Not all invasive species come from other countries. [IV] For example, lake trout, native to the Great Lakes, are considered invasive in Yellowstone Lake because they compete with native cutthroat trout for habitat and resources.

2. Human activities are the primary way invasive species spread, often unintentionally. Global travel and trade allow species to move quickly across ecosystems. Ships can carry aquatic organisms in their ballast water, while smaller boats transport species on their propellers. Insects can travel in wooden shipping crates or pallets, and ornamental plants may escape into the wild and spread. Released pets, like Burmese pythons in the Everglades, can also become invasive. Additionally, climate change worsens the situation by enabling invasive plants, like kudzu, and pests, like the mountain pine beetle, to expand into new areas.

3. Invasive species harm wildlife in various ways. Without natural predators, they can reproduce quickly and dominate ecosystems. Native animals often lack defenses or cannot compete with these aggressive species, which leads to disruptions in the ecosystem and poses serious challenges for native wildlife.

4. Direct threats from invasive species include preying on native wildlife, spreading diseases, and competing for food and resources. Indirectly, invasive species disrupt ecosystems by reducing biodiversity, destroying native food sources, and altering habitats. For instance, aggressive plants like kudzu can create monocultures, replacing diverse ecosystems. Some invasive species even change soil chemistry or increase wildfire risks. Preventing the spread of invasive species is essential to protect ecosystems and maintain biodiversity.

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

Read the following passage and choose the best answer to each of the following questions from 31 to 40.

1. [I] All living organisms on Earth need water to survive, but more than 100,000 species, including humans, require a special type of water called fresh water, which is found in limited amounts. [II] Freshwater ecosystems are made up of various plants, animals, microbes, soil, rocks, sunlight, and water that all interact around this valuable resource. [IV] Less than three percent of the Earth's total water is freshwater, and less than half of that is in liquid form. [IV]

2. Freshwater ecosystems naturally share resources between different habitats. For instance, rivers and streams transport salts and nutrients from higher elevations like mountains to lower areas, such as lakes, ponds, and wetlands. Eventually, these nutrients reach the ocean. These waterways also enable migrating species, such as salmon, to carry nutrients from the ocean back to freshwater ecosystems, providing essential support for these habitats upstream.

3. Lakes and ponds also undergo nutrient exchanges through seasonal cycles. Cold water, which is denser than warm water, sinks to the bottom, maintaining a more constant temperature. As winter arrives and the air temperature drops, the surface water becomes colder than the water at the bottom, causing it to sink and push the warmer water up. This process repeats in the spring when the ice melts, bringing nutrients from the lake's bottom to the surface, where they can be utilized by plants and animals.

4. It is normal for ecosystems to encounter change. Temperatures may fluctuate, populations may rise and fall, and rain may bring an abundance of water, then taper during drought. The plants, animals, and microbes in healthy freshwater ecosystems are resilient and have adaptations that allow them to adjust appropriately until ideal conditions resume. However, if any element of the ecosystem varies too far outside of the norm, the balance of the whole system can start to fail.

Where in paragraph 1 does the following sentence best fit?

The rest is stored as ice in polar caps and glaciers, making freshwater ecosystems an extremely precious and limited resource.

Read the following passage and choose the best answer to each of the following questions from 31 to 40.

1. [I] Invasive species pose a significant threat to ecosystems, wildlife, and human activities. [II] These species can include amphibians like cane toads, plants, insects, fish, fungi, bacteria, or even seeds and eggs that are not native to a specific area. [III] Not all invasive species come from other countries. [IV] For example, lake trout, native to the Great Lakes, are considered invasive in Yellowstone Lake because they compete with native cutthroat trout for habitat and resources.

2. Human activities are the primary way invasive species spread, often unintentionally. Global travel and trade allow species to move quickly across ecosystems. Ships can carry aquatic organisms in their ballast water, while smaller boats transport species on their propellers. Insects can travel in wooden shipping crates or pallets, and ornamental plants may escape into the wild and spread. Released pets, like Burmese pythons in the Everglades, can also become invasive. Additionally, climate change worsens the situation by enabling invasive plants, like kudzu, and pests, like the mountain pine beetle, to expand into new areas.

3. Invasive species harm wildlife in various ways. Without natural predators, they can reproduce quickly and dominate ecosystems. Native animals often lack defenses or cannot compete with these aggressive species, which leads to disruptions in the ecosystem and poses serious challenges for native wildlife.

4. Direct threats from invasive species include preying on native wildlife, spreading diseases, and competing for food and resources. Indirectly, invasive species disrupt ecosystems by reducing biodiversity, destroying native food sources, and altering habitats. For instance, aggressive plants like kudzu can create monocultures, replacing diverse ecosystems. Some invasive species even change soil chemistry or increase wildfire risks. Preventing the spread of invasive species is essential to protect ecosystems and maintain biodiversity.

The word aggressive in paragraph 3 could be best replaced by __________.

Read the following advertisement 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 1 to 6.

ANNOUNCEMENT

The Ho Chi Minh Communist Youth Union is pleased (1)______a field trip for qualified 12th-grade students. This is a wonderful opportunity to explore nature and learn about a (2)______.

Destination: Trang An Scenic Landscape Complex

Date: Saturday, January 20, 2025

Trang An is a mixed heritage site (3)______by UNESCO. It owes its beauty (4)______majestic limestone mountains and a network of unique caves. The area is also known for its stunning natural scenery. With its rich history, it is a destination that’s (5)______ for those who love discovering culture and nature.

The trip will include cave exploration, boat rides, and learning about the region's cultural landscapes. To (6)______a decision about joining, please contact your homeroom teacher to register before January 15.

Let’s plan a field trip filled with meaningful experiences and unforgettable memories!

Read the following passage and choose the best answer to each of the following questions from 31 to 40.

1. Natural hazards cause significant harm to both people and cultural heritage. They damage tangible heritage, such as buildings and infrastructure, as well as intangible heritage, like traditions, social values, and emotional connections to places. World Heritage sites, which protect both cultural and natural heritage, are also at risk. Disasters disrupt cultural systems, making communities more susceptible during and after these events.

2. [I] Culture plays an important role in how people view risks and respond to hazards. [II] From there, culture also influences people's risk indirectly because it impacts their livelihood choices, settlement location, social networks and availability for preparedness activities, including disaster risk reduction education. [III] These aspects affect how vulnerable a community is to natural hazards. [IV]

3. An increasing number of natural hazards are damaging heritage sites and disrupting cultural practices. This weakens the resilience of communities, particularly those that rely on heritage for local resources and sustainable development. Despite these threats, cultural and natural heritage can also strengthen communities by helping them adapt to risks and reduce their exposure to hazards, including climate change.

4. UNESCO protects cultural and natural heritage and uses it as a platform for disaster risk reduction. These efforts aim to build community resilience and ensure that no one is left behind.

5. World Heritage sites, Biosphere Reserves, and UNESCO Global Geoparks are essential for sustainable development. These sites protect natural and cultural heritage while promoting biodiversity and resource conservation. However, they face risks from natural hazards and extreme weather, which can affect nearby communities and resonate globally. At the same time, these sites educate people about disaster risks and solutions, offering opportunities to build safer, more resilient futures.

The word those in paragraph 2 refers to __________.

Read the following passage and choose the best answer to each of the following questions from 31 to 40.

1. [I] All living organisms on Earth need water to survive, but more than 100,000 species, including humans, require a special type of water called fresh water, which is found in limited amounts. [II] Freshwater ecosystems are made up of various plants, animals, microbes, soil, rocks, sunlight, and water that all interact around this valuable resource. [IV] Less than three percent of the Earth's total water is freshwater, and less than half of that is in liquid form. [IV]

2. Freshwater ecosystems naturally share resources between different habitats. For instance, rivers and streams transport salts and nutrients from higher elevations like mountains to lower areas, such as lakes, ponds, and wetlands. Eventually, these nutrients reach the ocean. These waterways also enable migrating species, such as salmon, to carry nutrients from the ocean back to freshwater ecosystems, providing essential support for these habitats upstream.

3. Lakes and ponds also undergo nutrient exchanges through seasonal cycles. Cold water, which is denser than warm water, sinks to the bottom, maintaining a more constant temperature. As winter arrives and the air temperature drops, the surface water becomes colder than the water at the bottom, causing it to sink and push the warmer water up. This process repeats in the spring when the ice melts, bringing nutrients from the lake's bottom to the surface, where they can be utilized by plants and animals.

4. It is normal for ecosystems to encounter change. Temperatures may fluctuate, populations may rise and fall, and rain may bring an abundance of water, then taper during drought. The plants, animals, and microbes in healthy freshwater ecosystems are resilient and have adaptations that allow them to adjust appropriately until ideal conditions resume. However, if any element of the ecosystem varies too far outside of the norm, the balance of the whole system can start to fail.

Which of the following is NOT mentioned as a feature of freshwater ecosystems?

Read the following passage and mark the letter A, B, C, or D on your answer sheet to indicate the  correct option that best fits each of the numbered blanks from 24 to 28.

Coincident with concerns about the accelerating loss of species and habitats has been a growing appreciation of the importance of biological diversity, the (24) _______ of species in a particular ecosystem, to the health of the Earth and human well-being. Much has been written about the diversity of terrestrial organisms, particularly the exceptionally rich life associated tropical rainforest habitats. Relatively little has been said, (25) _______ , about the diversity of life in the sea even though coral reef systems are comparable to rain forest in terms of richness of life.

An alien exploring Earth would probably (26) _______ priority to the planet's dominants – most distinctive feature - the ocean. Humans have a bias toward land (27) _______ sometimes gets in the way of truly examining global issues. Seen from far away, it is easy to realize that landmasses occupy only one-third of the Earth's surface. Given that two thirds of the Earth's surface is water and that marine life lives at all levels of the ocean, the total three-dimensional living space of the ocean is perhaps 100 times (28) _______ than that of land and contains more than 90 percent of all life on Earth even though the ocean has fewer distinct species.

Mark the letter A, B, C, or D on your answer sheet to indicate the correct answer to each of the  following questions.

In a marine _______, krill, animals similar to tiny shrimps, provide the main food source for the blue whale, an animal on the third trophic level.

Mark the letter A, B, C, or D on your answer sheet to indicate the word that differs from the other  three in the position of stress in each of the following questions.

Read the following passage and choose the best answer to each of the following questions from 31 to 40.

1. Extreme habitats are environments where most life, including humans, cannot survive. [I] These areas can be either very cold or very hot. [II] For example, polar regions are extremely cold, with temperatures often falling below 5°C. [III] Despite these harsh conditions, some microbes are able to live and even thrive in these areas. [IV] These bacteria are a type of psychrophile, which are microorganisms that grow best at temperatures of 15°C or lower.

2. On the other hand, some of the most extreme habitats are hot, with temperatures reaching over 40°C. These places are often near geothermal activity, such as deep-sea vents and hot springs. In 1966, microbiologist Thomas Brock discovered that microorganisms were surviving and growing in the hot springs of Yellowstone National Park. These organisms, known as thermophiles, require high temperatures to live. Deserts are also considered extreme hot environments. For example, the sidewinder snake has adapted to survive in the desert by moving in a way that only parts of its body touch the hot sand, reducing its exposure to the heat.

3. Organisms that survive in these extreme conditions can teach scientists important lessons. One example is the wood frog in Alaska (Lithobates sylvaticus). During winter, these frogs freeze completely, but when spring comes, they thaw and continue their lives. Scientists discovered that the frogs create chemicals that protect their organs from ice damage. This finding can help researchers develop methods to extend the preservation of human organs. Such advancements may be crucial for improving organ transplants.

4. Another remarkable organism is the tardigrade, also known as the water bear. This tiny creature can survive in many extreme environments, such as high mountains, deep oceans, and cold Antarctica. The water bear has even survived in space. By studying these organisms, scientists hope to learn more about life on other planets, such as Mars.

Which of the following is NOT mentioned as organisms that survive in extreme cold habitats?

Read the following passage and choose the best answer to each of the following questions from 23 to 30.

Sustainable Tourism in UNESCO World Heritage Marine Sites

1. On 5 December 2024, managers from 51 UNESCO World Heritage marine sites joined an online meeting with experts from UNESCO and the International Union for the Conservation of Nature (IUCN). The meeting aimed to provide site managers with knowledge and tools for sustainable tourism management. This would help them implement strategies to monitor and protect their sites from the harmful effects of over-tourism.

2. Tourism and UNESCO World Heritage marine sites are deeply interconnected, as these flagship marine protected areas (MPAs) often become major tourist destinations, drawing visitors from around the world. While tourism can foster economic growth and offer social benefits to local communities, it also presents risks. Uncontrolled development and excessive visitor numbers can threaten the integrity of these sites, especially as they face challenges like climate change and biodiversity loss.

3. During the meeting, managers shared their experiences and strategies. The Great Barrier Reef in Australia presented its sustainability framework, focusing on Protection, Presentation, and Partnership. This involves conservation, educating visitors, and using data to adjust management strategies. In Palau, the Rock Islands Southern Lagoon emphasized community-based efforts, strict visitor regulations, and cultural awareness, including the Palau Pledge, where visitors promise to respect the environment.

4. Global experts also shared effective practices for promoting sustainable tourism in protected areas. Peter Debrine from UNESCO highlighted the importance of managing visitor data and involving communities to protect these sites' Outstanding Universal Value (OUV). Arnau Teixidor from IUCN shared tools for promoting ecotourism and measuring impacts in Mediterranean marine areas. These approaches demonstrate how collaboration and innovative strategies can help balance tourism and conservation in marine protected areas.

Which of the following best paraphrases the underlined sentence in paragraph 4?

Choose 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. Huong: I can see the difference in the types of plants here.

b. Mr. Hung: Yes, and that variety is what makes this ecosystem so resilient and rich in life.

c. Huong: It's fascinating how animals can live in such different environments in the same place.

d. Mr. Hung: This ecosystem is unique because it has both forest and wetland areas.

e. Mr. Hung: That's because each area offers different resources for wildlife.

Read the following passage and choose the best answer to each of the following questions from 31 to 40.

1. Extreme habitats are environments where most life, including humans, cannot survive. [I] These areas can be either very cold or very hot. [II] For example, polar regions are extremely cold, with temperatures often falling below 5°C. [III] Despite these harsh conditions, some microbes are able to live and even thrive in these areas. [IV] These bacteria are a type of psychrophile, which are microorganisms that grow best at temperatures of 15°C or lower.

2. On the other hand, some of the most extreme habitats are hot, with temperatures reaching over 40°C. These places are often near geothermal activity, such as deep-sea vents and hot springs. In 1966, microbiologist Thomas Brock discovered that microorganisms were surviving and growing in the hot springs of Yellowstone National Park. These organisms, known as thermophiles, require high temperatures to live. Deserts are also considered extreme hot environments. For example, the sidewinder snake has adapted to survive in the desert by moving in a way that only parts of its body touch the hot sand, reducing its exposure to the heat.

3. Organisms that survive in these extreme conditions can teach scientists important lessons. One example is the wood frog in Alaska (Lithobates sylvaticus). During winter, these frogs freeze completely, but when spring comes, they thaw and continue their lives. Scientists discovered that the frogs create chemicals that protect their organs from ice damage. This finding can help researchers develop methods to extend the preservation of human organs. Such advancements may be crucial for improving organ transplants.

4. Another remarkable organism is the tardigrade, also known as the water bear. This tiny creature can survive in many extreme environments, such as high mountains, deep oceans, and cold Antarctica. The water bear has even survived in space. By studying these organisms, scientists hope to learn more about life on other planets, such as Mars.

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

Read the following passage and choose the best answer to each of the following questions from 31 to 40.

1. Extreme habitats are environments where most life, including humans, cannot survive. [I] These areas can be either very cold or very hot. [II] For example, polar regions are extremely cold, with temperatures often falling below 5°C. [III] Despite these harsh conditions, some microbes are able to live and even thrive in these areas. [IV] These bacteria are a type of psychrophile, which are microorganisms that grow best at temperatures of 15°C or lower.

2. On the other hand, some of the most extreme habitats are hot, with temperatures reaching over 40°C. These places are often near geothermal activity, such as deep-sea vents and hot springs. In 1966, microbiologist Thomas Brock discovered that microorganisms were surviving and growing in the hot springs of Yellowstone National Park. These organisms, known as thermophiles, require high temperatures to live. Deserts are also considered extreme hot environments. For example, the sidewinder snake has adapted to survive in the desert by moving in a way that only parts of its body touch the hot sand, reducing its exposure to the heat.

3. Organisms that survive in these extreme conditions can teach scientists important lessons. One example is the wood frog in Alaska (Lithobates sylvaticus). During winter, these frogs freeze completely, but when spring comes, they thaw and continue their lives. Scientists discovered that the frogs create chemicals that protect their organs from ice damage. This finding can help researchers develop methods to extend the preservation of human organs. Such advancements may be crucial for improving organ transplants.

4. Another remarkable organism is the tardigrade, also known as the water bear. This tiny creature can survive in many extreme environments, such as high mountains, deep oceans, and cold Antarctica. The water bear has even survived in space. By studying these organisms, scientists hope to learn more about life on other planets, such as Mars.

The word harsh in paragraph 1 could be best replaced by __________.