请教jj里的语法题目

1When an active tooth in the shark’s jaws is lost or worn down, many spare teeth lie in seemingly limitless reserve, each of which are ready to slide into the appropriate position.
A. When an active tooth in the shark’s jaws is lost or worn down, many spare teeth lie in seemingly limitless reserve, each of which are ready to slide into the appropriate position.

   each of 复数名词 + verb, 谓语动词使用单数，而且句子读起来别扭...
B. Whenever an active tooth is lost or worn down, many spare teeth lie in seemingly limitless reserve in the shark’s jaws, which are each ready to slide into the appropriate position.

   这里确实应该用are，但是which有修饰jaws的歧义
C. Many spare teeth lie in seemingly limitless reserve in the shark’s jaws, each one of which are ready to slide into the appropriate position when an active tooth is lost or worn down.

   which有指代jaws的歧义，each one of which后面应该用单数
D. The many spare teeth lying in seemingly limitless reserve in the shark’s jaws, each one of which is ready to slide into the appropriate position whenever an active tooth is lost or worn down.

   spare teeth前面加the不合理...它们之前并未被提到...which有指代jaws的歧义
E. In the shark’s jaws, many spare teeth lie in seemingly limitless reserve, each one ready to slide into the appropriate position whenever an active tooth is lost or worn down  

   我认为这个是对的。

请问单复数到底是啥?还有答案!!

2.Almost like clones in their similarity to one another, the cheetah species' homogeneity makes them especially vulnerable to disease.
A.    the cheetah species’ homogeneity makes them especially vulnerable to disease

   them指代错误
B.    the cheetah species especially is vulnerable to disease because of its homogeneity

   clones可以泛指“复制品”，但是这里clones是具体的而不是泛指 ，与后面的species不对称(突然想到后面还有个their.....)
C.   the homogeneity of the cheetah species makes it especially vulnerable to disease

    it指代歧义，cheetah 还是species ，homogeneity 与clones 不对称
D.   homogeneity makes members of the cheetah species especially vulnerable to disease

      homogeneity 与clones 不对称
E.    members of the cheetah species are especially vulnerable to disease because of their homogeneity

     clones与members对称，合理...

答案到底是b or e???