易错题中的疑惑1

12. Scientists believe that by (altering) the genetic compostion of plants it is possible to develop specimens that are (resisting) to (disease) and ( increase) food value.

key: b,  改为resistable还是什么?能讲讲道理吗?

15. While studying the (chemistry) (of human body), Dr. Rosalyn Yalow won a Nobel Prize for the research she (conducted on) the (role of ) hormones.

key: b, 难道是chemistry后的介词应该为at/between?

12.resistant.  前面已经有谓语are了，如果加ing是进行时。

resistable可被抵抗的，resistant具有抵抗能力的。

15.+the=>of the human body      

请问of 后面的名词加冠词有什么讲法吗？谢谢！

明白了，谢谢！