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四、(2025·南京市鼓楼区模拟)阅读理解。〔人与自然——宇宙探索〕
Have you ever wondered what it is like to be an astronaut? Astronauts face many challenges in space. Weightlessness is bad for human health. It can cause muscle and bone loss as well as vision(视觉) problems. Cosmic radiation(宇宙辐射) can harm their DNA. So, we need to understand how the human body changes in space. But researchers don't have a good understanding of what actually happens to DNA in space. Studying telomeres(端粒), the "end-parts" of chromosomes(染色体) that protect the ends of the DNA, may help.
Researchers know that telomeres get shorter as people get older. Stress, smoking and unhealthy environments make telomeres shorter, too. The length of telomeres is connected to the risk of heart disease and cancer. This makes them important to study for human health.
In 2015, NASA did a study on the twin astronauts Scott and Mark Kelly. Scott spent a year on the International Space Station while Mark stayed on Earth. Researchers found Scott's telomeres increased in length while in space. His telomeres then quickly shortened when he returned to Earth. In fact, his telomeres were even shorter than they had been before he went into space. The study gave researchers valuable new information about astronauts' health. To find out if the same changes happen during a shorter trip, another study was done on four astronauts who carried on a 3-day mission(任务). Their telomeres were longer during spaceflight. But when they returned to Earth, their telomeres shortened quickly. They slowly returned to normal length about 2 months later.
Both studies showed that space trips, even short ones, can change telomere length. Scientists think telomere length changes because of cosmic radiation exposure. Radiation, which is everywhere in space, can harm DNA. Spending more time in space also means more exposure. The International Space Station has protection in areas people use often. This helps protect the astronauts from some radiation. But what if humans want to travel to or stay on other planets someday? We need a better way to reduce radiation harm.
Space is a dangerous environment. We don't know a lot about how it can influence people's health for a long time, especially their DNA. The more we know, the better we will be able to keep our astronauts healthy. By learning more about changes like telomere length, scientists can find ways to protect future space travellers. As space tourism becomes more common, this knowledge will be key to keeping people safe and healthy in space.
1. Which problem may weightlessness bring to astronauts in space?
A. Cancer.
B. Bone loss.
C. Heart disease.
D. Hearing problems.
2. Why is studying telomeres important according to the passage?
A. Because it creates a healthy environment.
B. Because it helps reduce astronauts' stress.
C. Because it protects astronauts from radiation.
D. Because it shows how DNA changes in space.
3. What is the main purpose of this article?
A. To compare life on Earth and in space.
B. To share stories about famous astronauts.
C. To explain how space affects DNA and health.
D. To explain why space tourism develops rapidly.
Have you ever wondered what it is like to be an astronaut? Astronauts face many challenges in space. Weightlessness is bad for human health. It can cause muscle and bone loss as well as vision(视觉) problems. Cosmic radiation(宇宙辐射) can harm their DNA. So, we need to understand how the human body changes in space. But researchers don't have a good understanding of what actually happens to DNA in space. Studying telomeres(端粒), the "end-parts" of chromosomes(染色体) that protect the ends of the DNA, may help.
Researchers know that telomeres get shorter as people get older. Stress, smoking and unhealthy environments make telomeres shorter, too. The length of telomeres is connected to the risk of heart disease and cancer. This makes them important to study for human health.
In 2015, NASA did a study on the twin astronauts Scott and Mark Kelly. Scott spent a year on the International Space Station while Mark stayed on Earth. Researchers found Scott's telomeres increased in length while in space. His telomeres then quickly shortened when he returned to Earth. In fact, his telomeres were even shorter than they had been before he went into space. The study gave researchers valuable new information about astronauts' health. To find out if the same changes happen during a shorter trip, another study was done on four astronauts who carried on a 3-day mission(任务). Their telomeres were longer during spaceflight. But when they returned to Earth, their telomeres shortened quickly. They slowly returned to normal length about 2 months later.
Both studies showed that space trips, even short ones, can change telomere length. Scientists think telomere length changes because of cosmic radiation exposure. Radiation, which is everywhere in space, can harm DNA. Spending more time in space also means more exposure. The International Space Station has protection in areas people use often. This helps protect the astronauts from some radiation. But what if humans want to travel to or stay on other planets someday? We need a better way to reduce radiation harm.
Space is a dangerous environment. We don't know a lot about how it can influence people's health for a long time, especially their DNA. The more we know, the better we will be able to keep our astronauts healthy. By learning more about changes like telomere length, scientists can find ways to protect future space travellers. As space tourism becomes more common, this knowledge will be key to keeping people safe and healthy in space.
1. Which problem may weightlessness bring to astronauts in space?
A. Cancer.
B. Bone loss.
C. Heart disease.
D. Hearing problems.
2. Why is studying telomeres important according to the passage?
A. Because it creates a healthy environment.
B. Because it helps reduce astronauts' stress.
C. Because it protects astronauts from radiation.
D. Because it shows how DNA changes in space.
3. What is the main purpose of this article?
A. To compare life on Earth and in space.
B. To share stories about famous astronauts.
C. To explain how space affects DNA and health.
D. To explain why space tourism develops rapidly.
答案
1. B 2. D 3. C
