Sentence Structure

Can you check these?

Question 1: In the right amounts, greenhouse gases in the atmosphere trap heat from the Sun...................................................................... .

a- when they are able to afford a lengthy trip to the moon

b- as long as they are supported by national and international sponsors

c- even though it is not good for elderly to be exposed to intense sunlight

d- whereas there are many practical uses of such metals in industry

e- and thus the Earth becomes neither too hot nor too cold.

My answer is E

Question 2: ..................................................... , the fertile upper soil blows away or is eroded by rainwater

a- Once this area's vital fishing industry has been destroyed completely

b- Since it shows the changing global average surface temperatures

c- Even though diverting water from river and lakes caused desertification

d- When grass, bushes and trees in a piece of land die or are removed

e- Unless an area of relatively dry land became drier and desert-like

My answer is D