题目内容：

    Living with your parents has its advantages… at least when it comes to raising your kids—their grandkids. Because two new studies add to the evidence that grandmothers can improve the survival of grandchildren. That is, unless Grandma’s too old or lives too far away.

Humans are unusual in that women live long past the age at which they stop having babies. “We don’t really see that in nature. Most of the organisms (生物) will reproduce up to their very last moment,” says Patrick Bergeron, a teacher at Bishop’s University in Quebec. This increase in post-reproductive longevity (寿命) is often explained by the so-called “grandmother effect (效应)”.

To explore the “grandmother effect”, Bergeron and his researchers examined nearly 200 years’ worth of French-Canadian population records from the 17th and 18th centuries. At the time, life was hard. In some years, a third of the kids were not even making it to one year of age. But the researchers found that having a grandmother still alive was an advantage. Families with grandmothers alive were larger by about two and the survival of these grandchildren to age 15 was much improved.

This good effect was only seen when the grandmothers lived nearby, which suggests that grandmothers help by playing an active role in their grandchildren’s lives.

Unluckily, that role is harder for them to achieve as they get older, which brings us to the second study. Researchers at the University of Turku in Finland used church records from the 18th and 19th centuries. They found that the advantages connected with having a grandmother on hand depended on her age. Once grandmothers hit 75, the grandchild survival advantages disappeared. In other words, it was better for grandchildren to have no living grandmother at all than it was to live with an old one or one that was in poor health. So a healthy grandma helps make for a healthy grandchild

1.What’s “grandmother effect”?

A.Having a grandmother alive is an advantage.

B.Grandmothers are helpful to their children whatever their age.

C.Grandmothers are helpful for the survival of their grandchildren.

D.Healthy grandmothers living nearby are good for grandchildren’s health.

2.What can we know about the second study?

A.Researchers used French-Canadian population records.

B.Researchers used church records from the 17th and 18th centuries.

C.It was done by researchers from the University of Turku in Finland.

D.It found that it was good for grandchildren to have no living grandmother.

3.Where does this text probably come from?

A.A science report. B.A diary

C.A storybook. D.A textbook.