Answer:
It illustrates how volcanic rock contributed to the formation of two islands at different times in the earth's history.
Explanation:
It doesn't talk about B and C, but D doesn't make sense either because that only occurred to the Hunga island.
Answer:
The main idea is that she describes her grandmother's house as one that increased in size according to how many children she had. Every time that her grandmother became pregnant she would draw up plans so that her husband could build another room in the house.
C. is the correct answer. I hope this helps :)