问题
问答题
体育锻炼对心血管系统有哪些良好的影响。
答案
参考答案：要点：（1）对心的影响：心腔扩大，重量增加，心肌肥大，收缩功增强（4分）（2）对血管的影响：血管壁结构，冠状动脉，毛细血管（3分）
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体育锻炼对心血管系统有哪些良好的影响。
参考答案：要点：（1）对心的影响：心腔扩大，重量增加，心肌肥大，收缩功增强（4分）（2）对血管的影响：血管壁结构，冠状动脉，毛细血管（3分）
| Since life began eons ago, thousands of creatures have come and gone. Some, such as the dinosaurs, became extinct due to naturally changing ecologic conditions. More recent threats to life forms are humans and their activities. Man has drained marshes, burned prairies, dammed and diverted rivers. Some of the more recent casualties of man’s expansion have been the dodo, great auk, passenger pigeon, Irish elk, and Steller’s sea cow. Sadly, we can no longer attribute the increasing decline in our wild animals and plant species to "natural" processes. Many species are dying out because of exploitation, habitat alteration or destruction, pollution, or the introduction of new species of plants and animals to an area. As mandated by Congress, protecting endangered species, and restoring them to the point where their existence is no longer jeopardized, is the primary objective of the U.S. Fish and Wilidlife Service’s Endangered Species Program. |
The tone of this passage is
A．nationalistic.
B．pro-wildlife.
C．anti-wildlife.
D．feminist.