题目内容：

    A genetic variant(基因变体) that allows people to feel fully rested with fewer than six hours sleep a night has been found. It is the second such finding in recent months.

Ying-Hui Fu at the University of California, San Francisco, and her colleagues have been seeking out genetic variants responsible for short sleep and genetically engineering these variants into mice to confirm their effect. In August. the team found a variant in a gene called ADRB1, which allows 12 members of a family to sleep 4.5 hours per night without feeling tired.

Now the team has found a variant in a gene called NPSR1 in another family, in which one sleeps averaged 5.5 hours a night and the other just 4.3 hours, feeling fully rested. Another variant in NPSR1 has previously been linked to people requiring 20 minutes less sleep than average, based on studies of tens of thousands of people.

Generally, long-term lack of sleep can contribute to many disorders, including obesity, heart disease, high blood pressure and depression. As far as Fu’s team has been able to tell, however, people who sleep less with one of these gene variants are healthy and don’t appear to suffer any ill effects. However, to be absolutely sure would require long-term studies involving large numbers of people, which is not feasible(可行的).

It might be possible to develop drugs that mimic the effects of these variants. However, as NPSR1 is also involved in processes such as stress, anxiety and fear, there is a risk of serious side effects.

1.What did Fu’s team do to confirm the variants effect?

A.Observed blood pressure change.

B.Tested genetic variants on mice.

C.Sorted the effects of different genes.

D.Studied those sleeping less than average.

2.What can we learn about Fu’s team?

A.They are researching variants controlling sleep.

B.They study NPRS1 in a family of 12 members.

C.They have developed drugs to test normal people.

D.They will discover more variants in a week.

3.What does the word “mimic”in the last paragraph mean?

A.Reproduce. B.Compare. C.Avoid. D.Reduce.

4.Where does the text probably come from?

A.A news report. B.A health magazine.

C.A research paper. D.A biology textbook.