Cho bốn cung (trên một đường tròn định hướng): \(\alpha =-\frac{5\pi }{6};\,\beta =\frac{\pi }{3};\,\delta =\frac{19\pi }{6};\,\gamma =\frac{25\pi }{3}\). Các cung nào có điểm cuối trùng nhau?

Phát biểu nào sau đây là đúng?

Choose A, B, C or D to answer the question.

Which of the following situations best exemplifies “collaboration,” where individuals work together to achieve a common goal?

Khẳng định nào dưới đây là sai khi nói về máy tính?

Công ty A lên kế hoạch và tạo ra các sản phẩm văn phòng phẩm như bút, thước kẻ,...nhằm phục vụ cho việc sử dụng của người tiêu dùng đặc biệt là học sinh, sinh viên. trong trường hợp trên, công ty A đã thực hiện hoạt động nào của nền kinh tế?

Nội dung nào sau đây không phản ánh đúng vai trò của du lịch đối với việc bảo tồn di tích lịch sử và di sản văn hóa?

Chọn số liệu thích hợp để điền vào chỗ chấm trong câu sau: Thông thường, có khoảng ... lượng nước mà rễ cây hấp thụ được bị mất đi qua con đường thoát hơi nước.

Tài nguyên khoáng sản đa dạng ở khu vực Mỹ Latinh là cơ sở để phát triển ngành nào sau đây?

Đâu là nguyên nhân gây bệnh bên trong?

Phát biểu nào sau đây đúng khi nói về điểm khác biệt trong chức năng của DNA và RNA?

Một bạn học sinh thực hiện thí nghiệm sau:

- Cho vào bát sứ khoảng 2 mL dầu thực vật (hoặc khoảng 2 gam mỡ) và \(4-5 \mathrm{mL}\) dung dịch \(\mathrm{NaOH} \ 40 \%\).

- Đun hỗn họp sôi nhẹ và khuấy đều bằng đũa thủy tinh, thỉnh thoảng cho vài giọt nước cất để tránh hỗn hợp bị cạn.

- Đun khoảng 10 phút thì dừng, cho thêm 10 mL dung dịch NaCl bão hòa vào và khuấy đều.

Nhận xét nào dưới đây là đúng về thí nghiệm trên?

Thuận lợi chủ yếu về tự nhiên để ngành công nghiệp ở Cộng hòa Nam Phi phát triển là gì?

Cho bảng số liệu lượng mưa các tháng năm 2023 tại trạm quan trắc Đà Nẵng:

Theo bảng số liệu và dựa vào kiến thức đã học, phát biểu nào sau đây đúng về mùa mưa ở Đà Nẵng?

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.  

The phrase These organisms in paragraph 1 refers to...

Read the following passage about Singapore Science Centre 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.

The Singapore Science Centre, situated on a sprawling six-hectare site in Jurong, offers a captivating way to explore the wonders of science and technology. Here, visitors can engage with interactive exhibits that make learning both fun and memorable. Clap your hands, and colorful bulbs will light up; spin a wheel, and it will activate a fan. This engaging environment sparks curiosity and fuels the imagination of both children and adults.

The centre boasts more than four hundred exhibits across various fascinating topics, including solar radiation, communication, electronics, mathematics, nuclear energy, and evolution. These exhibits are designed to foster interest in science and technology among the public, making the centre a hub for educational exploration.

Notably, it is the first science centre to be established in Southeast Asia. Officially opened in 1977, the centre now welcomes an average of 1,200 visitors daily, highlighting its enduring popularity and educational value.

The exhibits are thoughtfully arranged across four main galleries: the Lobby, Physical Sciences, Life Sciences, and Aviation. To ensure a fresh and engaging experience, the exhibits are renewed annually, encouraging repeat visits. Visitors are encouraged to interact with the exhibits, as opposed to traditional “hands-off” policies in most museums. Here, pushing buttons, turning cranks, or pedaling mechanisms are all part of the fun and learning experience.

The Discovery Centre, added in 1985, is specially designed for children aged three to twelve, providing an exciting space for young minds to explore and experiment. Most recently, a stone-age exhibit was introduced, showcasing extinct animals and early human life, offering insights into prehistoric times.

With its interactive displays and immersive environment, the Singapore Science Centre continues to inspire a love for science and discovery, making it an unforgettable destination for learners of all ages.

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

Phương trình \(\sqrt {x - 1} = x - 3\) có tập nghiệm là?

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 23 to 30.

SCREEN TIME: MENTAL HEALTH MENACE OR SCAPEGOAT?

    "Have smartphones destroyed a generation?" Jean Twenge - a psychology professor at San Diego State University - asked in her controversial book, iGen. In the book, she argues that those born after 1995 are facing "a mental-health crisis", and she believes it can be linked to growing up with their noses pressed against a screen. Her newest study provides more support for that connection, showing that teens who spent more than an hour or two a day interacting with their gadgets were less happy on average than those who had more face time with others.

    Twenge's conclusions have come up against criticism in the past. Some have accused her work of oversimplifying or overlooking data that may tell a slightly different story. Twenge recognises that her study suggests only a link between screen use and psychological well-being. A possible explanation is that kids are running to their screens to escape from the things in life that are making them unhappy. However, the surveys can't say whether screen time directly changes teens' mental health, the research states.

    Philanthropist Melinda Gates, whose three children were also born after 1995, wrote in The Washington Post, "phones and apps aren't good or bad by themselves, but for adolescents who don't yet have the emotional tools to overcome life's problems, they can aggravate the difficulties of growing up."

    At the same time, she said, kids are learning on their devices and connecting in novel ways. Other studies have explored the connection between social media and isolation and how "likes" activate the brain's reward centre. Some analyses have found that moderate use of these technologies is not harmful in itself and can even improve children's social skills and build emotional strength.

In which paragraph does Jean Twenge discuss the emotional impact of screen time on teens?

Cho \({\log _a}b = 4\). Giá trị của \({\log _a}\left( {{a^3}{b^2}} \right)\) bằng?