Khi nói về hiện tượng phóng xạ, phát biểu nào dưới đây là sai?

Cho nguyên tố X có số hiệu nguyên tử là 18, vị trí của nguyên tố trong bảng tuần hoàn các nguyên tố hoá học là

Khi cây trưởng thành, lượng nước thoát qua bề mặt lá chiếm

Đường đặc trưng vôn – ampe của hai điện trở \(R_1\) và \(R_2\) ở \(20 ^\circ C\) được thể hiện như hình vẽ. Khi mắc nối tiếp 2 điện trở này để tạo thành bộ điện trở thì điện trở tương đương của bộ bằng bao nhiêu?

Qua quan sát, A biết thị trường đang rất thiếu mít không hạt để bán. Điều này thể hiện chức năng nào của thị trường?

Quốc gia nào sau đây ở khu vực Mỹ Latinh có quy mô GDP trên 1000 tỉ USD?

Đâu không phải là dịch vụ lưu trữ qua điện toán đám mây?

These volunteers mainly provided services and help for children with cognitive ___ (impair).

Điểm nào sau đây không thuộc đồ thị hàm số \(y = \frac{{\sqrt {{x^2} - 4x + 4} }}{x}.\) 

Trong một máy tăng áp lí tưởng đang hoạt động ở chế độ không tải. So sánh đúng giữa suất điện động cảm ứng trong một vòng của cuộn sơ cấp es và suất điện động cảm ứng trong một vòng của cuộn thứ cấp e_t là

Read the passage below and choose A, B, C or D.

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 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.

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 does the author probably support?

Để đóng cắt và bảo vệ mạch điện sử dụng máy bơm trong gia đình có công suất 750 W, điện áp 220 V và hệ số công suất là 0,8 nên chọn aptomat có dòng điện định mức là tho

Nước chiếm tỉ lệ bao nhiêu trong sinh khối tươi của mô thực vật?

Tên khoa học của ruồi đục quả là:

Nguyên tố potassium thuộc ô 19 trong bảng tuần hoàn. Cấu tạo nguyên tử này là

Để làm xà phòng thủ công, người ta đun dầu thực vật hoặc mỡ động vật với dung dịch kiềm. Khi đó muối của kim loại kiềm với acid béo được tạo thành ở dạng keo. Các muối này được tách ra, sao đó trộn với các chất phụ gia, hương liệu, chất tạo màu,... rồi ép thành bánh xà phòng mà chúng ta vẫn đang sử dụng hàng ngày.

-> Trong xà phòng làm thủ công không có thành phần nào dưới đây?

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:

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Are you looking to get ___(1)___ shape but don’t know where to start? Our online fitness platform gives you access to the best workouts to fit your schedule. Whether you prefer yoga, cardio, or strength training, we’ve got something for everyone. You can ___(2)___ our workouts anytime, anywhere, without needing any special equipment. Plus, our expert trainers are always available to help ___(3)___ your form and provide tips for improvement. Don't wait to ___(4)___ your fitness goals – sign up today and enjoy a free month of workouts! No matter your fitness level, you'll ___(5)___ results and feel better than ever. Remember, your journey ___(6)___ with the first step.

Nguyên nhân chủ yếu gây nên bệnh ung thư, tự miễn, AIDS là gì?

Vào cuối thế kỉ XIX - đầu thế kỉ XX, đế quốc nào dưới đây được mệnh danh là “đế quốc mà Mặt Trời không bao giờ lặn”?

Read the passage carefully. Choose an option (A, B, C or D) that best answers each question from 23 to 30.

1. How do children learn about wildlife? And is what they learn the sort of thing they should be learning? It is my belief that children should not just be acquiring knowledge of animals but also developing attitudes and feelings towards them based on exposure to the real lives of animals in their natural habitats. But is this happening?

2. Some research in this area indicates that it is not. Learning about animals in school is often completely disconnected from the real lives of real animals, with the result that children often end up with little or no understanding or lasting knowledge of them. They learn factual information about animals, aimed at enabling them to identify them and have various abstract ideas about them, but that is the extent of their learning. Children's storybooks tend to personify animals as characters rather than teach about them.

3. For direct contact with wild and international animals, the only opportunity most children have is visiting a zoo. The educational benefit of this for children is often given as the main reason for doing it but research has shown that zoo visits seldom add to children's knowledge of animals – the animals are simply like exhibits in a museum that the children look at without engaging with them as living creatures. Children who belong to wildlife or environmental organizations or who watch wildlife TV programmes, however, show significantly higher knowledge than any other group of children studied in research. The studies show that if children learn about animals in their natural habitats, particularly through wildlife-based activities, they know more about them than they do as a result of visiting zoos or learning about them in the classroom.

4. Research has also been done into the attitudes of children towards animals. It shows that in general terms, children form strong attachments to individual animals, usually their pets, but do not have strong feelings for animals in general. This attitude is the norm regardless of the amount or kind of learning about animals they have at school. However, those children who watch television wildlife programs show an interest in and affection for wildlife in its natural environment, and their regard for animals in general is higher.

What could be the best title for the passage?