Trong dao động điều hòa với phương trình $x=A\cos\left(\omega t+\varphi\right)$, nhận xét nào dưới đây là đúng?

Rễ cây trên cạn hấp thụ nước và ion muối khoáng chủ yếu qua miền nào?

Hành vi vi phạm quyền và nghĩa vụ về tự do ngôn luận, báo chí và tiếp cận thông tin gây nên nhiều hậu quả tiêu cực, ngoại trừ việc:

Trong thí nghiệm xác định có sự tạo thành tinh bột trong quá trình quang hợp ở cây xanh,việc đặt cây thí nghiệm vào chỗ tối 2 ngày nhằm

Tin sinh học là sự hợp của những lĩnh vực nghiên cứu nào?

Phương pháp nào thường được sử dụng để biểu hiện diện tích và sản lượng lúa của các tỉnh nước ta trong cùng một thời gian?

Việt Nam có thể học hỏi bài học kinh nghiệm nào từ công cuộc cải cách mở cửa ở Trung Quốc?

When Jane feared she'd ______ her keys again, she quickly checked to see if they were _________ in her pocket.

Đặc điểm nào sau đây không phải là đặc điểm của kháng sinh tốt?

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.

In which space (marked A, B, C and D in the passage) will the following sentence fit?

Without them, plants that normally rise in trees’ shadows are suddenly exposed to higher temperatures and bright light.

Những loài động vật nào dưới đây có hệ tuần hoàn hở?

Mark the letter A, B, C or D on your answer sheet to indicate the sentence that is closest in meaning to each of the following questions: 

I thought I should not stay at home yesterday.

Kế hoạch tài chính cá nhân trung hạn thường có thời hạn khoảng bao lâu?

Sau Chiến tranh thế giới thứ hai, phong trào giải phóng dân tộc ở châu Phi diễn ra sớm nhất tại khu vực nào? 

Trong chuyển động thẳng biến đổi đều, véctơ gia tốc tức thời có đặc điểm:

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.

Biting into a ripe, juicy fruit brings a smile to many people’s faces. But eating that same fruit a week before it is ripe probably wouldn’t be as enjoyable! Unripe fruits are often hard and bitter, but that serves a purpose. The hard exterior of an unripe fruit protects the developing seed inside. After a seed fully develops inside the fruit, the fruit changes color, softens, and gets sweeter to become more attractive to animals and humans. These organisms eat the fruit and spread its seeds, ensuring the plant’s survival and regrowth.

But how does a fruit ripen? The ripening process involves many complex chemical reactions. When a fruit ripens, it goes through a chemical change. A chemical change happens when bonds within molecules break, and the atoms that once formed them regroup into new molecules. Chemical changes are irreversible. Once a fruit ripens, it cannot become unripe again.

One molecule responsible for this chemical change is ethylene. Ethylene (C2H4) is a colorless gas made up of carbon and hydrogen atoms. (I). It is a naturally occurring molecule in the atmosphere. (II). It is also an important plant hormone. (III). Plants release ethylene through the growing tips of roots, flowers, and ripening fruit. (IV). Although ethylene serves other purposes in plants, one of its main purposes is to trigger the chemical reactions that cause fruits to ripen. As the fruit matures, oxygen in the air helps stimulate the production of ethylene. This ethylene production is a signal that begins fruit ripening. For that reason, unripe fruits have low levels of ethylene, while ripe fruits have higher levels of ethylene. Most fruits produce ethylene and respond to ethylene in the atmosphere.

Although fruits require ethylene to ripen, different types of fruits respond to this molecule in two distinct ways: non-climacteric fruits and climacteric fruits. Non-climacteric fruits do not ripen after harvesting. They produce very little ethylene of their own. Climacteric fruits, on the other hand, continue to ripen after they are picked. These fruits produce a large amount of ethylene. Climacteric fruits can also speed up the ripening process of other fruits nearby since they release high levels of ethylene into the air.  

Which of the following best paraphrases the underlined sentence: The ripening process involves many complex chemical reactions.

Giberelin chủ yếu sinh ra ở bộ phận nào của thực vật?

Read the following passage about global warming 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.

ADMIRING A U.S. PRESIDENT

One of the most influential figures in American history is Franklin D. Roosevelt, who served as the 32nd President of the United States. (18) ______. He is known for his leadership during the Great Depression and World War II. His New Deal programs aimed to provide relief for the unemployed and stimulate economic recovery. Roosevelt’s ability to communicate with the American people through his fireside chats (19) ______.

His policies helped reshape the role of the federal government in the economy, leading to lasting changes that continue to impact the nation today. (20) ______. Roosevelt's vision for a more inclusive America resonated with many citizens, and his commitment to social welfare programs has left a significant legacy.

Additionally, his determination and resilience during his battle with polio (21) ______. This experience shaped his empathy for the struggles of others and influenced his approach to governance. His leadership style is often admired for its ability to unite the country in times of crisis. (22) ______. His enduring impact is evident in the policies and institutions that were established during his presidency. 

Read the following passage about the Pathways from Today's Actions to Tomorrow's World 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.

As we stand at the crossroads of environmental decision-making, the actions we take today will shape our world in 2050. Scientists warn that we're skating on thin ice with current consumption patterns and carbon emissions. Global temperatures could rise by 2-4 degrees Celsius unless significant changes occur within the next decade. Many countries have pledged to achieve carbon neutrality by 2050, but these promises require immediate implementation. Individual choices in transportation, energy usage, and consumption can collectively influence whether future generations inherit a sustainable planet or face severe climate consequences.

[I] Technological innovation represents our greatest hope for addressing environmental challenges by 2050. [II] Renewable energy sources like solar and wind are becoming increasingly affordable, potentially replacing fossil fuels entirely within thirty years. [III] Electric vehicles may dominate transportation networks, while vertical farming could transform food production in urban areas. [IV] However, these technological solutions must be developed and deployed equitably to avoid creating new disparities between wealthy and developing nations.

Social structures will undergo dramatic transformation by 2050 as demographic shifts reshape communities worldwide. Aging populations in developed countries will necessitate new approaches to healthcare, retirement, and social support systems. Meanwhile, climate migration may force millions to relocate from vulnerable coastal and drought-prone regions. Education systems must evolve to prepare our students for jobs that don't yet exist, emphasizing their adaptability and lifelong learning. Cities will need to become more resilient, incorporating green spaces and sustainable infrastructure to support growing populations.

Economic models must fundamentally change by 2050 to balance prosperity with environmental responsibility. The traditional focus on continuous growth may shift toward measuring success through wellbeing indicators rather than GDP alone. Circular economy principles will likely replace linear production models, with products designed for reuse and recycling. Resource-sharing platforms may become more prevalent, reducing individual consumption while maintaining living standards. Companies implementing genuinely sustainable practices will thrive, while those clinging to environmentally harmful methods may disappear entirely. The transition presents both challenges and opportunities for businesses willing to embrace innovation and sustainability.

Which of the following can be inferred from the passage?

Công của lực điện trường dịch chuyển một điện tích 5.10^-6 C ngược chiều một đường sức trong một điện trường đều 1000 V/m trên quãng đường dài 0,5 m là

GPS do quốc gia nào dưới đây xây dựng, vận hành và quản lí?