Số tập con của tập A = {1; 2; 3} là

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 passage about the Science in Service of Humanity 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.

Science has come out of its shell in laboratories to become a powerful force for human advancement. Modern scientific endeavors increasingly focus on addressing real-world challenges affecting communities globally. From developing vaccines that save millions to creating technologies connecting people across continents, science serves humanity in countless ways. This shift represents a fundamental evolution in how we perceive scientific progress—not merely academic pursuit but a practical tool for improving lives and solving pressing problems.

[I] Medical breakthroughs exemplify how science directly benefits humanity. [II] For instance, gene therapy offers hope for those with inherited conditions, while artificial intelligence helps diagnose diseases earlier and more accurately. [III] These advancements didn't happen overnight; scientists had to burn the midnight oil for years before achieving success. [IV] Their perseverance demonstrates that when science targets humanitarian goals, results can transform society profoundly.

Environmental science has emerged as another crucial domain where laboratory work translates into human welfare. Climate scientists provide data informing policy decisions affecting billions. Conservation biologists develop strategies to protect biodiversity, ensuring future generations benefit from natural resources. Agricultural researchers create drought-resistant crops helping communities withstand changing climate conditions. Despite these contributions, environmental science faces challenges including funding limitations, political resistance, and urgency of addressing accelerating climate change. Nevertheless, dedicated scientists continue their work, recognizing environmental health directly impacts human wellbeing.

The future of science in service of humanity looks increasingly collaborative and inclusive. Modern approaches incorporate diverse perspectives, including indigenous knowledge and community participation. Citizen science projects engage non-professionals in data collection, democratizing the scientific process. Open-access publishing makes research findings available to anyone with internet access, not just wealthy institutions. These developments suggest science's greatest potential lies in becoming more accessible and responsive to human needs. As we face complex global challenges, from pandemics to climate change, science serving humanity offers our best hope for a sustainable future.

The phrase “come out of its shell” in paragraph 1 could be best replaced by _________.

What is the most _______ city in the world?

Chọn cặp từ/ cụm từ thích hợp nhất điền vào chỗ trống.

Người chủ có thể quan sát những biểu hiện _____ của thú nuôi nhưng đa số mọi người không ai biết những âm thanh đùng đoàng do bắn pháo hoa tác động thế nào đến động vật _____.

Khi quân Pháp bị sa lầy ở Đà Nẵng và Gia Định (1858-1860), thái độ của triều đình nhà Nguyễn là gì?

Chị C là nội trợ thường xuyên đi siêu thị để mua thực phẩm và các đồ gia dụng trong nhà. Trong trường hợp này chi C đóng vai trò là chủ thể gì của nền kinh tế?

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.

The explosion in mobile phone use around the world has made some health professionals worrieSome 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.

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.

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.

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.

Which of the following best paraphrases this sentence: “Phones are more than a means of communication - having a mobile phone shows that they are cool and connected.”?

Cho \(\text{tan}\alpha =2\). Giá trị của \(A=\frac{3\text{sin}\alpha +\text{cos}\alpha }{\text{sin}\alpha -\text{cos}\alpha }\) là

Trong không gian Oxyz, mặt phẳng \((P)\) đi qua điểm \(N(3 ;-2 ; 6)\) và vuông góc với trục Ox có phương trình là:

Kiểu dữ liệu nào sau đây không được đề cập trong chương trình tin học phổ thông?

Cho biết năng lượng liên kết của H–F là 565 KJ mol^-1; H–Cl là 431 KJ mol^-1; H–Br là 364 KJ mol^-1; H–I là 297 KJ mol^-1. Trong các liên kết trên, liên kết nào bền nhất?

Đến năm 2020, guốc gia nào sau đây ở châu Phi thuộc thành viên của G20?

Đâu là nguyên nhân gây bệnh bên trong?

Nguyên tử nguyên tố X có hai lớp electron, trong đó có 1 electron độc thân. X có thể là

Quy trình thiết kế kĩ thuật bao gồm mấy bước?

Trong số \(50\) học sinh của lớp 10A có \(15\) bạn được xếp loại học lực giỏi, \(25\) bạn được xếp loại hạnh kiểm tốt, trong đó có \(10\) bạn vừa được xếp loại học lực giỏi vừa được xếp loại hạnh kiểm tốt. Khi đó, lớp 10A có bao nhiêu bạn được khen thưởng, biết rằng muốn được khen thưởng bạn đó phải có học lực giỏi hoặc hạnh kiểm tốt. 

Theo quy định của pháp luật, công dân được ứng cử vào các cơ quan đại biểu của nhân dân là người như thế nào?

Một vật đang nằm yên trên mặt đất, lực hấp dẫn do Trái đất tác dụng vào vật có độ lớn

Đọc đoạn thơ sau và trả lời câu hỏi:

Đường nở ngực. Những hàng dương liễu nhỏ

Đã lên xanh như tóc tuổi mười lăm.

Xuân ơi Xuân, em mới đến dăm năm

Mà cuộc sống đã tưng bừng ngày hội

Như hôm nay, giữa công trường đỏ bụi

Những đoàn xe vận tải nối nhau đi

Hồng Quảng, Lào Cai, Thái Nguyên, Việt Trì

Tên đất nước reo vui bao tiếng gọi...

(Tố Hữu, Bài ca mùa xuân 1961, dẫn theo thivien.net)

Đoạn thơ trên KHÔNG sử dụng biện pháp nghệ thuật nào?

Chọn phát biểu đúng. Cho biểu thức: x or y: