题目内容：

Is there a way to turn back the aging process in people? For centuries, people have been looking for a “fountain of youth.” The idea is that if you find a magical fountain, and drink its water, you will not age.

Researchers in New York did not find an actual fountain of youth, but they may have found a way to turn back the aging process. It appears that the answer may be called the hypothalamus, which is part of your brain. It controls important body activities, including growth, the way we process food and so on.

Researchers at New York’s Albert Einstein College of Medicine found that hypothalamus neural stem cells (干细胞) also influence how fast aging takes place.

Dongsheng Cai, a professor at the Albert Einstein College of Medicine, was the leading researcher in a study on aging in mice. He and his team reported their findings.

“Aging speed can be controlled by a particular place in the body, which is the hypothalamus. And it can be controlled by a particular type of cells, which are hypothalamus stem cells.” He adds that when the hypothalamus starts aging, so does the body. So when hypothalamus function is in decline, particularly the loss of hypothalamus stem cells, and this protection against the aging development is lost, it eventually leads to aging.

Using this information, the researchers began trying to activate the hypothalamus in laboratory mice. They did this by injecting the animals with stem cells.

The researchers say the results show that the treatment slowed aging in the animals. “When we injected the hypothalamus stem cells to the middle-aged mice, the mice aged slowly and they can also live longer.”

But these results were just from studying mice in a laboratory. If the mice can live longer, does that mean people could have longer lives? The next step is to see if the anti-aging effects also work in human beings.

“If we can translate what we have seen in animals to humans, I think humans can function better during later ages.” Cai and his team say their studies may have other benefits. They say the findings could lead to new ways to help doctors identify and treat any number of age-related health issues.

1.Why does the author mention the “fountain of youth” in the first paragraph?

A. To explain what the “fountain of youth” is.

B. To introduce the hypothalamus.

C. To show how to find the “fountain of youth”.

D. To help people find the “fountain of youth”.

2.What does the underlined word “it” in Paragraph 2 refer to?

A. The brain.    B. The aging process.

C. Hypothalamus.    D. The stem cell

3.What do we know about the study done by Cai?

A. They have found a way to turn back the aging process.

B. The brain controls growth, reproduction and the way we process food.

C. The decrease of hypothalamus stem cells can lead to aging.

D. The finding has been applied to human beings.

4.Which of the following can be the best title of the passage?

A. The Fountain of Youth

B. A New Discovery about Aging

C. The Ways of Slowing Down Aging

D. Hypothalamus—the Fountain of Youth