Cho các phát biểu sau:
(1) Có khoảng 25 nguyên tố hóa học thiết yếu.
(2) Có 2 loại nguyên tố thiết yếu: nguyến tố đa lượng và nguyên tố vi lượng.
(3) Carbon là nguyên tố có vai trò đặc biệt quan trọng đối với tế bào.
(4) Các nguyên tố hóa học chỉ tham gia cấu tạo nên các đại phân tử sinh học.
Số phát biểu đúng khi nói về nguyên tố hóa học trong tế bào là
Hãy suy nghĩ và trả lời câu hỏi trước khi xem đáp án
- (1) Sai. Có khoảng 17 nguyên tố thiết yếu cho sự sống.
- (2) Đúng. Các nguyên tố thiết yếu được chia thành hai loại: đa lượng và vi lượng.
- (3) Đúng. Carbon là nguyên tố quan trọng tạo nên bộ khung của các hợp chất hữu cơ.
- (4) Sai. Các nguyên tố hóa học tham gia cấu tạo nên nhiều hợp chất khác nhau trong tế bào, không chỉ đại phân tử sinh học. Ví dụ: nước, muối khoáng,...
Câu hỏi liên quan
Read the following passage about managing change 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.
Growing up in Athens, Greece, Lydia Borsi remembers feeling tested when she tried to deal with mental health issues. Borsi says she had been seeing a therapist for anxiety. But she notes that people in Greece do not openly discuss mental health issues, which also get little attention in general healthcare services. “It was a lot more secretive. And people thought that I was a lot more unique,” Borsi said.
That all changed in 2017 when she moved to the United States to study at the University of Rochester in Rochester, New York. “When I came here, I really liked that people were not afraid to speak up about mental health and say that it’s important,” she said. The university was very supportive of her needs and offered plenty of information. She also became involved with a school group called Active Minds that helps students deal with mental health issues. [A]
Then due to the spread of the novel coronavirus, the University of Rochester had to move all its classes and some of its mental health resources online. Luckily, Borsi was able to connect with a mental health expert outside the school, in the local community. [B]
But as many of her American friends returned home, Borsi was stuck. Greece had succeeded in limiting the spread of the virus within its borders, but flights there from the U.S. are barred until July. Also, the health crisis has put her plans to seek admission to medical school in Britain on hold. [C] And she is not alone.
[D] In April, Active Minds launched a survey of over 2,000 students at U.S. colleges and universities. The study found that over 80 percent of those asked said the coronavirus crisis had negatively affected their mental health. One in five said it has affected them severely.
Laura Horne, chief program officer at Active Minds, says the findings are especially troubling given that the crisis is only going to make it harder for colleges and universities to help these students. “Colleges and universities had to pivot rather quickly to respond to COVID-19 and figure out all facets of university life, including mental health services. Now they have to figure out how to communicate with students,” Horne said.
Frank Chen is a Houston, Texas-based psychiatrist who has worked with college-age young adults. He points out that individuals at that age are in an important stage of their mental development. And college can be a difficult experience for students with or without mental health issues, as they balance work, studies, and personal relationships. Adding a major world event, like the spread of the coronavirus, makes it very difficult to predict what the long-term psychological effects might be. “I don’t think that there’s another event in the history of the people who are alive now that can really measure up to this,” said Chen.
The word ‘barred’ in paragraph 4 is closest in meaning to
Các phương thức chăn nuôi chủ yếu ở nước ta là ?
Nội dung nào thể hiện vai trò của hoạt động tiêu dùng đối với sản xuất?
Read the following passage about Huawei company 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.
Over the past few decades, the term ‘Hallyu’, which translates to “Korean Wave”, has made its way to the global stage. The rapid growth of the Hallyu market owes its success to meticulously crafted domestic cultural strategies and unwavering government support. Following the Asian financial crisis in 1997, President Kim Dae-jung envisioned a national cultural strategy to revive the economy. Since then, South Korea’s cultural industry has been on an upward tendency.
Amongst the latest ranking of most-subscribed-to YouTube accounts, BLACKPINK secures the global top spot of artists, followed by BTS in second place and Justin Bieber in third place. The exportation of cultural industries vividly showcases the escalating influence of Hallyu, now a trump card for South Korea in improving its soft power.
BLACKPINK’s recent presence at Buckingham Palace is not the first time South Korean idol groups have stepped onto the diplomatic stage. Thanks to the huge fan base and influence of these groups, they have become a common sight before foreign affairs visits and leader summits. Back in May 2022, BTS held an audience with US President Joe Biden at the White House, discussing matters concerning anti-Asian hate and racial discrimination.
According to the ‘2021 National Image Survey’ by the South Korean Ministry of Culture, Sports, and Tourism, a striking 80.5% of foreigners positively evaluated South Korea’s national image. Undoubtedly, the Hallyu wave molds South Korea’s national image on their political and cultural fronts.
Which of the following is NOT mentioned as a reason for the popularity of Hallyu?
Cho mệnh đề sau: “… x ∈ ℝ, 4x2 – 1 = 0”.
Chỗ trống trong mệnh đề trên có thể điền kí hiệu nào dưới đây để mệnh đề đúng?
Theo đồ thị ở hình dưới đây, vật chuyển động thẳng đều trong khoảng thời gian
Cho dãy số \(\left( {{u}_{n}} \right)\) là cấp số cộng với \({{u}_{1}}=3\); \({{u}_{8}}=24\) thì \({{u}_{11}}\) bằng
- Máy tính thực hiện mấy bước để xử lí thông tin?
Một ô tô có khối lượng 1500kg chuyển động đều qua đoạn cầu cong vòng lên có bán kính cong là 80m với vận tốc 36km/h. Lấy \(g = 10m/{s^2}\). Áp lực mà xe lên cầu khi qua vị trí cao nhất có giá trị là
Tôi mồ côi cha năm hai tuổi
Mẹ tôi thương con không lấy chồng
Trồng dâu, nuôi tằm, dệt vải
Nuôi tôi đến ngày lớn khôn.
Hai mươi năm qua tôi vẫn nhớ
Ngày ấy tôi mới lên năm
Có lần tôi nói dối mẹ
Hôm sau tưởng phải ăn đòn.
Nhưng không, mẹ tôi chỉ buồn
Ôm tôi hôn lên mái tóc
- Con ơi
trước khi nhắm mắt
Cha con dặn con suốt đời
Phải làm một người chân thật…
(Trích Lời mẹ dặn – Phùng Quán)
Xác định nội dung chính của đoạn thơ trên.
Phần II. Trắc nghiệm đúng, sai
Cho các tập hợp sau:
\(A = \left\{ {\left. {x \in \mathbb{R}} \right|\left( {{x^2} + 7x + 6} \right)\left( {{x^2} - 4} \right) = 0} \right\};\,B = \left\{ {\left. {x \in \mathbb{N}} \right|2x \le 8} \right\};\,C = \left\{ {\left. {2x + 1} \right|x \in \mathbb{Z}, - 2 \le x \le 4} \right\}\).
a) Tập hợp \(A\) có 3 phần tử.
b) \(A \cup B = \left\{ { - 6; - 2; - 1;0;1;2;3;4} \right\}\).
c) \(A \cap B = \left\{ 2 \right\}\).
d) \(A \cup C = \left\{ { - 6; - 3; - 2;2;3;5;7;9} \right\}\).
Find the word which has a different sound in the part underlined.
Xác định vận tốc của mỗi chuyển động dựa vào đồ thị dưới.
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
[I] A newborn baby can see, hear and feel. By the age of five, a child can talk, ride a bike and invent imaginary friends. How does this development happen? [II]We don't understand the way language, thinking and planning develop very well. [III]Now scientists are using new technology to ‘see’ into children's brains. And they are discovering new information about the way a baby's brain develops. [IV]
A study in 2010 showed that children who were afforded more focus often gained an edge in IQ. The brain of a newborn infant contains nearly a hundred billion neurons. This number is comparable to that of an adult's brain. As they mature, an infant assimilates information through the sensory modalities of sight, hearing, smell, taste, and touch. This information fosters intricate connections between different regions of the brain. By the age of three, there are approximately a hundred trillion synaptic connections.
One experiment looked at images of babies' brains while they were listening to different sounds. The sounds were in different sequences. For example, one sequence was mu-ba-ba. This is the pattern ‘A-B-B’. Another sequence was mu-ba-ge. This is the pattern ‘A-B-C’. The images showed that the part of the brain responsible for speech was more active during ‘A-B-B’ patterns. This shows that babies can tell the difference between different patterns. This experiment is interesting because sequences of words are important to grammar and meaning. Compare two sentences with the same words in a different order: ‘John killed the bear’ is very different from ‘The bear killed John.’ So babies are starting to learn grammatical rules from the beginning of life.
Researchers also know that babies need to hear a lot of language in order to understand grammar rules. But there is a big difference between listening to television, audiobooks or the internet, and interacting with people. One study compared two groups of nine-month-old American babies. One group watched videos of Mandarin Chinese sounds. In the other group, people spoke the same sounds to the babies. The test results showed that the second group could recognize different sounds, however, the first group learned nothing. The scientist, Patricia Kuhl, said this result was very surprising. It suggests that social experience is essential to successful brain development in babies.
The word “recognize” in paragraph 4 is OPPOSITE in meaning to:
Đơn vị của thế năng là
Khai triển đa thức \(P(x)=(1+2 x)^{12}=a_{0}+a_{1} x+\ldots+a_{12} x^{12}\). Tìm hệ số \(a_{k}(0 \leq k \leq 12)\) lớn nhất trong khai triển trên.
Khi một vật nhận nhiệt từ môi trường, nội năng của vật sẽ
Xác suất tìm thấy electron trên toàn bộ vùng không gian xung quanh hạt nhân là bao nhiêu phần trăm?
Nguồn năng lượng chủ yếu được con người tiêu thụ để phục vụ đời sống xã hội, sản xuất công nghiệp trong thời đại ngày này là
Xét hai xe A và B chuyển động cùng nhau vào hầm Thủ Thiêm dài 1 490 m. Xe A chuyển động với tốc độ ban đầu trước khi vào hầm là 60 km/h và chuyển động chậm dần đều với gia tốc 144 km/h2, xe B chuyển động chậm dần đều với gia tốc 120 km/h2 từ lúc bắt đầu chạy vào hầm với tốc độ 55 km/h. Nhận định nào sau đây là đúng về thời gian chuyển động của hai xe trong hầm?