一道sat语法题! greatly affected the ecosystems of some southeast

一道sat语法题!
greatly affected the ecosystems of some southeast swamplands.
D.the trapping and removel of large alligators
答案说选D,为什么原来不对?
还有一道填空的
The editor removed large portions of the manuscripe,entire paragraphs that she considered either erroneous or
A.revising.decorous
D.expurgating...offensive
为什么啊,她删的部分是既不错误也不偏激的?
我觉得选A