求教几道语法题

crystalcat001UID: 2121144

By focusing on the interesting, _____ the significant, the penny press newpapers of the 1830's helped to change the concept of news.
A which does not necessarily
B not necessarily
C was not necessarily
D nor necessarily being
KeyB，不太明白，可是总觉得题目significant前面加the怪怪的

Almost every the hereditary material of an individual organism resides in the chromosomes.
KeyA.不知道怎么改

Someone may refuse to recognize the serousness of an emetionally threatening situation and perceive as less threatening.
key:perceive as 是去掉as吗？

上面都是错题里找出来的，真的是弄不明白了，大家帮帮忙啊:)