Cho hình chóp \[S.ABC\], có \(SA = SB = SC\), đáy là tam giác đều cạnh bằng \(7\). Biết thể tích khối chóp \[S.ABC\] bằng \(\frac{{343\sqrt 3 }}{3}\). Tính khoảng cách giữa hai đường thẳng \(SA\) và \(BC\).

Điểm khác nhau giữa hệ tuần hoàn ở người và hệ tuần hoàn ở cá là

Theo Đacuyn, nhân tố chính trong quá trình hình thành những đặc điểm thích nghi trên cơ thể sinh vật qua chọn lọc tự nhiên (CLTN) là gì?

Chuỗi truyền electron phân bố ở đâu?

Kiến giải nào dưới đây là đúng khi cho rằng: Toàn cầu hóa là một xu thế khách quan, một thực tế không thể đảo ngược?

Dựa vào thông tin dưới đây để trả lời các câu từ 12-14

“Về quan hệ giữa đổi mới kinh tế và đổi mới chính trị, phải tập trung làm tốt đổi mới kinh tế, đáp ứng những đòi hỏi cấp bách của nhân dân về đời sống, việc làm và các nhu cầu xã hội khác, xây dựng cơ sở vật chất – kĩ thuật của chủ nghĩa xã hội, coi đó là điều kiện quan trọng để tiến hành thuận lợi đổi mới trong lĩnh vực chính trị. Đồng thời đổi mới kinh tế phải từng bước đổi mới tổ chức và phương thức hoạt động của hệ thống chính trị, phát huy ngày càng tốt quyền làm chủ và năng lực sáng tạo của nhân dân trên các lĩnh vực chính trị, kinh tế, văn hóa, xã hội”.

(Đảng Cộng sản Việt Nam, Văn kiện Đại hội đại biểu toàn quốc lần thứ VII, NXB Sự thật, Hà Nội, 1991, tr.54)

Đổi mới kinh tế được coi là điều kiện quan trọng và phải

Cho tam giác ABC có BC = a, $\widehat{BAC}=135°$. Trên đường thẳng vuông góc với $\left(ABC\right)$ tại A, lấy điểm S thỏa mãn $SA=a\sqrt{2}$. Hình chiếu vuông góc của A trên SB, SC lần lượt là M, N. Số đo góc giữa hai mặt phẳng $\left(ABC\right)$ và $\left(AMN\right)$ bằng?

Những thành tựu của công cuộc Đổi mới ở Việt Nam từ năm 1986 có giá trị nào sau đây?

Read the passage carefully

1. Do you find yourself yawning all day at school? You probably need more sleep. However, it is not just how much sleep you get that is important. What you do before bedtime also has a huge effect on how you feel the next day. If you spend time chatting to someone on social media, or reading a book on your e- reader, you are not alone.

2. All devices' screens give out a large amount of blue light, which affects the body's production of the sleep hormone, melatonin, which can change your sleep patterns. So it is not just getting to sleep that becomes hard, but the quality of your sleep also suffers. The result is that you can wake up several times during the night, and have difficulty getting up in the morning.

3. Sleep is food for the brain, so not sleeping well can be a severe problem for anyone, especially for teenagers, because their brains are still developing. When you do not sleep well, it can be difficult to concentrate at school, which makes it harder to learn and get good grades. It can also affect your mood, making you feel sad or anxious. 

4. So, it is clear you should not use your phone before you go to sleep. Why not leave it in another room? Nothing on social media is so important that it cannot wait a few hours! You should rediscover paper books and enjoy feeling tired and sleepy before bedtime rather than wondering why your best friend has not liked your photo! How will you wake up? You do not have to use the alarm on your phone. Go and buy yourself an old-fashioned alarm clock! The negative effects that screen time is having on sleep have been in the news a lot recently, so manufacturers of smartphones and tablets have added a feature to the mobile devices that can help reduce these. Most new phones have a night-time setting that changes the colour of the screen so that it gives out less blue light. If you really cannot avoid going onto social media at bedtime, think about turning on this setting on your phone.

(Adapted from Prepare)

Why does the author mention the sentence "How will you wake up?"?

Trong y học, tia X thường dùng để chụp xương là do

Đuôi tệp của tệp ảnh động khi xuất là gì?

Read the following advertisement about a new travel platform 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. (1,5 points)

DISCOVER NEW TRAVEL BUDDIES WITH TRAVELMATE

"Who will you explore your next destination with? Will they share the same (1) ____________ for adventure, or will they prefer a more relaxing trip?" If you often wonder (2) ____________ your travel companions before your next vacation, we have exciting news for you! TravelMate, a (3) ____________, allows you to select your future travel buddies before your trip. This service is designed to give you a more enjoyable and personalized experience. All you need to do is share your travel preferences with the platform, and you'll be matched with others (4) ____________ similar tastes. Whether you're looking to make new friends or reconnect with previous ones, TravelMate (5) ____________ it easy. If you're seeking adventure or simply want (6) ____________ a relaxing getaway, there's a perfect match waiting for you!

Read the following passage about human life expectancy 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. 

How long will a baby born today live? 100 years? 120 years? Scientists are studying genes that could mean long life for us all.

There are already many, many people who have passed the landmark age of 100. In fact, there are now so many healthy, elderly people that there’s a name for them: the wellderly. These are people over the age of eighty who have no major illnesses, such as high blood pressure, heart disease or diabetes.

There are many scientific studies of communities where healthy old age is typical. These include places like Calabria in southern Italy and the island of Okinawa in Japan. In Calabria, the small village of Molochio has about 2,000 inhabitants. And of these, there are at least eight people over a hundred years old. When researchers ask people like this the secret of their long life, the answer is almost always about food and is almost always the same: ‘I eat a lot of fruit and vegetables.’ ‘I eat a little bit of everything.’ ‘I neither smoke nor drink.’

In the past, scientists looked at things such as diet and lifestyle for an explanation of long life, but these days they are also looking at genetics. Researcher Eric Topol says that there must be genes that explain why people are protected from the effects of aging process. The new research into long life did scrutinize groups of people who have a genetic connection. One interesting group lives in Ecuador. In one area of the country there are a number of people with the same genetic condition. It’s called Laron syndrome. These people don’t grow very tall – just over one metre. But Laron syndrome also give them protection against cancer and diabetes. As a result, they live longer than other people in their families. Meanwhile, on the Hawaiian island of Oahu, there’s another group of long-lived men, Japanese-Americans. They have a similar gene to the Laron syndrome group.

Back in Calabria, researchers constructed the family trees of the 100-year-old people. They looked at family information from the 19th century to today. It is concluded that there are genetic factors that give health benefits to the men. This is a surprising result because generally in Europe, women live longer than men. So what really makes people live longer? It seems likely that it is an interaction of genes, the environment and probably a third factor – luck.

In which paragraph does the writer mention that most people talk about what to eat as the secret of their long life?

Chất nào sau đây được coi là nhiên liệu của tương lai?

Ngành du lịch không có vai trò nào sau đây?

Tập nghiệm $S$ của phương trình ${{5}^{2{{x}^{2}}-x}}=5$ là

Phương trình \({\log _{\frac{1}{2}}}x =  - 2\) có nghiệm là?