根据下列文章,请回答 21～25 题。 Text 1 A finding in recent years shows that men cannot

根据下列文章,请回答 21～25 题。

Text 1

A finding in recent years shows that men cannot manufacture blood as efficiently as women can. This makes surgery riskier for men. Because they do not breathe as often as women, men also need more oxygen. But men breathe more deeply and this exposes them to another risk. They draw more of the air when it is polluted.

Men's bones are larger than women's and they are arranged somewhat differently. The feminine walk that evokes so many whistles is a matter of bone structure. A man has broader shoulders and a narrower pelvis, which makes him stride out with no waste motion. A woman's wider pelvis,designed for childbearing, forces her to put more movement into each step she takes with the result that she displays a bit of jiggle and sway as she walks.

If you think a man is brave because he can climb a ladder to clean out the roof gutters, don't forget it is easier for him than for a woman. The angle at which a woman's thigh is joined to her knees makes climbing difficult for her, no matter whether it is a ladder or stairs or a mountain that she is tackling.

A man's skin is thicker than a woman's and not nearly as soft. This prevents the sun's radiation from getting through, which is why men wrinkle less than women do. Women have a thin layer of fat just under the skin and there is a plus to this greater fat reserve. It acts as an invisible fur coat to keep a woman warmer in the winter. Women also stay cooler in summer. Because the fat layer helps insulate them against heat. Men's fat is distributed differently. And they do not have that layer of it underneath their skin. In fact, they have considerably less fat than women and more lean mass.41 percent of a man's body is muscle compared to thirty-five percent for women,which means that men have more muscle power. When we mention strength, almost 90 percent of a man's weight is strength compared to about 50 percent of a woman's weight.

The higher proportion of muscle to fat makes it easier for men to lose weight. Muscle burns up five more calories a pound than fat does just to maintain itself. So when a man wants to loss weight, the pounds roll off much faster. For all men's muscularity they do not have the energy reserves women do. They have more start-up energy ,but the fat tucked away in women's nooks and crannies provides a rich energy reserve that men lack.

Cardiologists at the University of Alabama who tested healthy women on treadmills discovered that over the years the female capacity for exercise far exceeds the male capacity. A woman of sixty who is in good health can exercise up to 90 percent of what she could do when she was twenty. A man of sixty has only 60 percent left of his capacity as a twenty-year-old.

第 21 题 That boys suffer more from air pollution can possibly be justified by the fact that

A．the male have larger bones than the female.

B．women can manufacture blood more efficiently than men.

C．men usually breathe more deeply than women.

D．women breathe as often as men.