The subordinate clause here is A, "as the layers of ash slowly compressed". Subordinate means that it cannot exist on its own, it has to be a part of the main, independent clause.
I believe the correct choice of answer would be A. Hope this helps!
Answer:
c
Explanation:
because of the quote "imagine my humiliation" and "the best example of my brilliance with machines " it shows how self-aware
Answer:
A
Explanation:
it describes its features