题目

Almost everyone has some kind of hobby.  61   may be anything from collecting stamps to making model planes. Some hobbies are very expensive, but   62   are valuable only to their owners. I know a man who has a coin collection worth several thousand dollars. A short time ago he bought a seldom   63   (see) fifty-cent piece worth $250! He was very happy about what he bought and thought the price was  64   (reason).  65   the other hand my youngest brother collects match boxes. He has almost 600 of them but I doubt   66   they are worth any money. However, to my bro 右图表示生物多样性的三个不同层次，下列叙述正确的是 A．图Ⅰ、Ⅱ、Ⅲ分别表示遗传（基因）多样性、种群多样性和生态系统多样性 B．图Ⅰ说明基因重组导致多种等位基因的产生，从而形成遗传多样性 C．图Ⅱ反映出生殖隔离的生物可以在同一个环境中相对稳定地共存 D．图Ⅲ反映出的河流、森林和城市生态系统具有相同的小气候特点