题目内容：

    It often seems that some people possess superhuman eating powers, allowing them to eat an entire pizza while remaining slim. Others only eat a slice but gain five pounds. Now one doctor says there' s evidence that genetics could be behind some of these differences. Regardless of how much you eat, your weight may be out of control.

Vann Bennett, a biochemist at Duke University and his team led a new study and discovered why this happens. They engineered mice to have several common modifications of the gene found in humans. They observed that mice who had mutations of ankyrin-B(锚蛋白B的变异) took more glucose(葡萄糖) into their fat cells, which in turn made more fat. Typically, the cell membrane( 膜) acts as a barrier to prevent glucose from entering these cells ; the change kept the gate open. The change may serve a useful purpose. “ Probably this is not always a bad thing,” Bennett told Newsweek. “It could help people survive hunger in the past. But today we have so much food that it probably is a bad thing.”

Dieters have long been told to watch their calories and exercise more, but this new finding suggests that a common approach doesn't work for everyone. Our metabolism( 新陈代谢) naturally slows with age, making it harder to maintain the weight of our 30-year-old selves when we' re 50. Now add an uncontrollable ankyrin-B gene, and it may seem impossible to stay slim.

The mice in the study gained more weight when on high-fat diets. Despite being studied in mice, the researchers believe further research on this gene could potentially create a field of customized diets and health plans based on genetics. Bennett imagines such assessments being performed at birth one day. For now, disappointed dieters can take comfort with one saying: It's not you, it's your genes.

1.How did a mouse gain weight with mutations of ankyrin-B?

A.The ankyrin-B could make the mouse eat more.

B.The fat cells in the mouse would take more glucose to create more fat.

C.The glucose could function as a barrier to prevent the fat from reducing.

D.The cell membrane in the mouse could open the gate of fat into the mouse.

2.What was the effect of the change in the past in paragraph 2?

A.It could help people to avoid fat food.

B.It could help people to absorb more nutrition.

C.It could help people to get through the starvation.

D.It could help people to enjoy more delicious snacks.

3.Why is it more difficult to stay slim when we are older?

A.Because we all lack exercise. B.Because we have ankyrin-B genes.

C.Because we watch our calories less. D.Because our metabolism weakens.

4.What can be expected from further research?

A.It may help people to maintain the weight.

B.It may provide more comfort for the depressed dieters.

C.It may change many new-born babies’ gene arrangement.

D.It may present human beings with a series of health plans.