Notice there is a
comma before the underlined part!
That comma means that there are two cases:
1. we have an "and", then the underlined part
cannot be parallel with "causing a rise" because
"A, and B" pattern is wrong. Therefore, the underlined part must be parallel with "will endanger human health". (
actually you can very easily approach this by thinking through the meaning, but I am talking in the scope of grammar)
2. we have an "as well as", then the underlined part
must be parallel with "causing a rise" because it follows the format of
"A , as well as B". By the rules above, we can eliminate A, C, E because they are not parallel.
We are left with B and D. However, the meaning in D is illogical: the action of "endanger human health" cannot cause "threaten global ecological systems". Therefore, B correct.
Again, we should always approach SC questions through meaning. But here I am actually working in terms of grammar first just to show you guys the difference between "and" and "as well as".