Số lớn nhất được viết bằng cách dùng cả năm chữ số 0 ; 6 ; 4 ; 1 ; 9 (mỗi chữ số chỉ được viết một lần) là số nào?

Phiên mã ngược là quá trình tổng hợp DNA dựa trên khuôn mẫu RNA. Quá trình này được xúc tác bởi một loại enzyme đặc biệt gọi là enzyme phiên mã ngược (RT: reverse transcriptase). Enzyme này có cả hoạt tính DNA polymerase và hoạt tính RNase H. Cũng giống như DNA polymerase trong quá trình tái bản DNA, enzyme phiên mã ngược đòi hỏi phải có primer (mồi) đặc biệt để tổng hợp nên DNA mới.

Enzyme phiên mã ngược được phát hiện lần đầu tiên ở retrovirus. Sau khi các retrovirus đi vào tế bào vật chủ, genome của RNA của nó sẽ được phiên mã ngược thành DNA sợi đôi, rồi tích hợp vào DNA của vật chủ.

Tại sao hiện tượng phiên mã ngược thường được phát hiện ở retrovirus?

Đối với điện trường xung quanh một điện tích điểm Q đặt trong chân không, độ lớn của vectơ cường độ điện trường tại một điểm M không phụ thuộc vào

Tình huống nào dưới đây có hành vi vi phạm đạo đức trong kinh doanh?

Điền cụm từ còn thiếu vào chỗ trống

Mô hình chăn nuôi hiện đại được chia làm 2 loại: … và …

Read the following passage about Generations Z and Alpha: Born Multicultural Citizens 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.

Generation Z, born between 1997 and 2012, has grown up in a world (18)_________. These young people use smartphones and computers every day to talk with friends from different parts of the world. If they had been born 30 years earlier, they would not have had these opportunities to experience global connections. They are learning about different cultures, languages, and traditions not just from books but through real online friendships.

Generation Alpha, which includes children born after 2013, is even more connected. The toys that Generation Alpha plays with often teach them about global issues while they have fun. Many schools (19)_________. These young students, who come from diverse backgrounds, are creating a new kind of society where differences are celebrated.

(20)_________. Generation Z students participate in exchange programs and travel more than previous generations did. (21)_________, sharing their daily lives and learning from each other.

The world that these generations are creating will be more inclusive and understanding. Traditional borders are becoming less important while cultural exchange is valued more highly. Generation Z and Alpha children, (22)_________, will likely become adults who solve problems together across cultural lines. The future looks promising with these multicultural citizens leading the way.

Trên vỏ một tụ điện có ghi 20 pF – 200 V. Tụ điện tích trữ được năng lượng tối đa là

Read the passage carefully. Choose an option (A, B, C, or D) that best answers each question from to 646 to 650:

1. Millions of people are using cellphones today. In many places, it is actually considered unusual not to use one. In many countries, cellphones are very popular with young people. They find that the phones are more than a means of communication - having a mobile phone shows that they are cool and connected.

2. The explosion in mobile phone use around the world has made some health professionals worried. Some doctors are concerned that in the future many people may suffer health problems from the use of mobile phones. In England, there has been a serious debate about this issue. Mobile phone companies are worried about the negative publicity of such ideas. They say that there is no proof that mobile phones are bad for your health.

3. On the other hand, medical studies have shown changes in the brain cells of some people who use mobile phones. Signs of change in the tissues of the brain and head can be detected with modern scanning equipment. In one case, a traveling salesman had to retire at young age because of serious memory loss. He couldn't remember even simple tasks. He would often forget the name of his own son. This man used to talk on his mobile phone for about six hours a day, every day of his working week, for a couple of years. His family doctor blamed his mobile phone use, but his employer's doctor didn't  agree.

4. What is it that makes mobile phones potentially harmful? The answer is radiation. High-tech machines can detect very small amounts of radiation from mobile phones. Mobile phone companies agree that there is some radiation, but they say the amount is too small to worry about.

5. As the discussion about their safety continues, it appears that it's best to use mobile phones less often. Use your regular phone if you want to talk for a long time. Use your mobile phone only when you really need it. Mobile phones can be very useful and convenient, especially in emergencies. In the future, mobile phones may have a warning label that says they are bad for your health. So for now, it's wise not to use your mobile phone too often.

What is the word “potentially” in paragraph 4 closet in meaning to?

Phản ứng hoá học nào dưới đây là phản ứng oxi hoá-khử?

Loài vi sinh vật sống dựa vào nguồn năng lượng từ các hợp chất vô cơ và nguồn cacbon từ CO₂ được xếp vào kiểu dinh dưỡng gì?

Bản vẽ lắp thể hiện:

Trên thị trường, doanh nghiệp Q nhận thấy giá của nguyên vật liệu đang có xu hướng gia tăng, nhưng hợp đồng đã kí với đối tác không thể thay đổi giá, nên doanh nghiệp đã quyết định cắt giảm một số chi phí về xử lý chất thải để giữ chi phí sản xuất sản phẩm không tăng, đảm bảo được mức lợi nhuận ban đầu. Trong trường hợp trên, doanh nghiệp Q đã làm gì để đảm bảo được mức lợi nhuận ban đầu?

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 20 to 27.

Traditional Media

Before the invention of newspapers, the main source of news was word of mouth. Any writings and drawings were done by hand. Although printing presses had existed in eastern Asia, it was Gutenberg’s invention in Europe in 1453 that made printing faster and books more accessible. It reduced the cost and size of printed books and made them the first form of mass media affordable to less wealthy people. Gutenberg’s invention also quickened the spread of discoveries and information, and promoted literacy in Europe.

The printing press led to the rise of printed newspapers that appeared regularly. The first newspapers developed from around 1612 and in a short period of time, they became very popular in Europe and the European colonies. In the 19th century, they also appeared in Asia.

Newspapers and magazines are still very popular today. Although most of them have online versions, many people continue to read print media, which is considered more credible than digital media.

In the 1920s, when radio, television, and video were introduced, the phrase “the media” began to be used. Black and white television quickly became popular in the 1950s, and in the 1960s colour broadcasts started in many countries. Thanks to its audiovisual presentation, television became one of the most important forms of mass media in the 20th century. As a source of news, entertainment, and education, it still attracts a large number of viewers today.

(Adapted from English Workbook 12 – Global Success)

Which of the following best paraphrases the underlined sentence in paragraph 1?

Trong trường hợp nào ta cần tiến hành cập nhật hồ sơ học sinh của nhà trường?

Hình thức của cách mạng tư sản Anh là gì?

Kiến thức về địa lí tự nhiên không định hướng ngành nghề gì?

Read the following passage about Renewable energy sources 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] Renewable energy sources, such as solar, wind, and hydroelectric power, have gained global popularity as a sustainable alternative to fossil fuels. [II] Unlike coal and oil, renewable energy generates electricity without releasing harmful emissions, making it a cleaner option for the environment (Jacobson et al., 2017). [III] However, despite the advantages of renewable energy, there are still notable challenges that need to be addressed for it to fully replace traditional energy sources (Ell Abban et al., 2014). [IV]

          One major advantage of renewable energy is its sustainability. Renewable resources, unlike fossil fuels, are naturally replenished and do not deplete over time. For instance, solar power harnesses energy from sunlight, which is virtually endless. In addition, renewable energy contributes to reducing greenhouse gas emissions, which helps combat climate change. Many countries are increasingly investing in renewable technologies to decrease their carbon footprint and meet international climate goals.

          However, renewable energy has certain limitations. One significant issue is its intermittent nature; for example, solar and wind power depend on weather conditions, making it difficult to generate a consistent power supply. This variability can disrupt the energy grid, which relies on a steady supply of electricity to meet demand. Another challenge is the high initial cost of setting up renewable energy facilities. Although prices have decreased in recent years, installing solar panels or wind turbines still requires substantial upfront investment (IRENA, 2019).

          Despite these challenges, advancements in technology are gradually making renewable energy more efficient and accessible. Improved energy storage systems, such as batteries, allow excess power generated during favourable conditions to be stored and used later, ensuring a more reliable energy supply. As technology and infrastructure improve, renewable energy may eventually.

Which of the following can be inferred from the passage?

Dựa vào bản đồ dưới đây (Atlat Địa lí Việt Nam, Nxb Giáo dục Việt Nam, 2024) và kiến thức đã học, trả lời các câu hỏi dưới đây.

Chế độ nhiệt nước ta có sự phân hóa đa dạng do tác động chủ yếu của

Read the following passage about education in Nepal 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. 

A few years ago, amid a record drought, scientists noticed something odd. A few of California’s giant sequoias inside Sequoia and Kings Canyon National Parks were dying in ways no one had ever documented – from the top down. When researchers climbed into the canopies, they discovered that beetles had bored into a few branches. By 2019, at least 38 of the trees had died – not a large number, but "concerning because we’ve never observed this before,” says Christy Brigham, the park’s chief of resource management.

Scientists had assumed that stately sequoias, with their bug-repelling tannins, were immune to dangerous pests. Worried experts are investigating whether some mix of increased drought and wildfire, both worsened by climate change, have now made even sequoias susceptible to deadly insect invasions.

If so, these ancient sentinels would be just the latest example of a trend experts are documenting around the world: Trees in forests are dying at increasingly high rates—especially the bigger, older trees. According to a study in the journal Science, the death rate is making forests younger, threatening biodiversity, eliminating important plant and animal habitat, and reducing forests’ ability to store excess carbon dioxide generated by our consumption of fossil fuels. [A]

There is no single direct cause. Decades of logging and land clearing play a role, scientists say. But increasing temperatures and rising carbon dioxide from the burning of fossil fuels have significantly magnified most other causes of tree death. Scientists are documenting longer and harsher droughts, more severe outbreaks of insects and disease, and increasingly catastrophic wildfires.

With 60,000 known tree species on Earth, those shifts are playing out differently across the planet. In central Europe, for instance, “You don’t have to look for dead trees,” says Henrik Hartmann, with Germany's Max Planck Institute for Biogeochemistry. “They’re everywhere.” In one recent year, following a week of excessive heat, hundreds of thousands of beech trees dropped their leaves. Even in colder regions, “You get a couple of hot years and the forests are suffering,” says Hartmann. “There are individual species that are being driven beyond the threshold of what they can handle.” [B]

Just last year, massive fires marched through a dry Australia, smoldered across 7.4 million acres in northern Siberia, and focused the world’s attention on blazes in the Amazon.

The consequences of all these changes around the world are still being assessed. The first national look at tree mortality in Israel showed vast stretches disappearing, thanks largely to scorching heat and wildfires. [C] In a country largely blanketed by stone and sand, forests mean a great deal. Trees support nests for eagles and habitat for wolves and jackals. They hold soil with their roots. [D]

“We’re dealing with a very tough situation. It’s a race to the unknown,” says Tamir Klein at the Weizmann Institute of Science.

What does ‘these ancient sentinels’ in paragraph 3 refer to?

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. 

Boosting Your Confidence

Looking to improve your self-esteem and feel more confident in your daily life? Here’s how you can make positive changes!

Confidence Facts: Studies show that only 35% of people report feeling confident in their abilities, while others ___(7)___ with self-doubt. Building confidence can help improve your performance at work and in social situations.

Tips to Boost Your Confidence:

● Set realistic goals! Start small and ___(8)___ yourself when you reach milestones.

● Surround yourself with positivity! Seek ___(9)___ supportive friends and colleagues to boost your self-esteem.

● Focus on your strengths! ___(10)___ dwelling on mistakes, concentrate on what you do well.

● Practice self-care! Taking time for yourself can ___(11)___ your mood and confidence levels.

● Keep learning! Gaining new skills helps ___(12)___ a sense of accomplishment.