WELLINGTON, September 19 (Xinhua) -- If your teenage son won't get out of bed in the morning, then take comfort from the fact that he might be sleeping his way to a healthier future, according to a new research from New Zealand.
Researchers in human nutrition at the University of Otago have found that teenage boys who sleep less have more body fat when compared to girls, for whom lack of sleep has no noticeable effect on their body fat ratios.
The study of 386 boys and 299 girls aged 15 to 18 found that average-sized 16-year-old boy weighing 69.5 kg and 176 cm tall, who slept for eight hours a day, had a waist size l.8 cm bigger and l.6 kg, or 9 percent, more body fat than the average-sized boy who slept 10 hours a day.
"The boys who slept eight hours a day would also have l.8 kg more lean (bone and muscle) mass compared to the boys who slept 10 hours, but that's only a 1.4-percent increase, compared to the 9- percent increase seen in body fat," said lead researcher from the Department of Human Nutrition, Dr. Paula Skidmore.
"Our results suggest that for older teenage boys, making sure that they get enough sleep may help to maintain a healthier body. It seems to be that, within reason, the more sleep the better for boys," Skidmore said in a statement Thursday.
"It was unexpected that we did not find the same result in girls, who may actually be more aware of their diet and more in tune with a healthier lifestyle."
The researchers ruled out the effects of food choice and number of screens, such as televisions, games and consoles, which the teenagers had in their bedrooms.
What's the research really about?

A．Boys and girls.

B．Food and weight.

C．Sleep and health.

D．Screens and fat.

What's the result of less sleep for teenage boys?

A．Bigger waist and more fat in the body.

B．An increase in weight and height.

C．More concerned with their diet.

D．A decrease in bone and muscle.

From the sixth paragraph we can infer that ______.

A．girls usually sleep less and have healthier lifestyles than boys

B．the researchers expected to see the same result in girls

C．peoples' diet has a great effect on their health

D．boys are usually lazier than girls

Who would be the most pleased to hear the news?

A．Teachers.

B．Girls.

C．Parents. .

D．Boys.