Answer:
I believe the answer is B.
Explanation:
Hope my answer has helped you and if not i am sorry.
5: true
6: Oxygen
7: H+
8: true
The answer is D
One way to remember this is when you are building a bridge there is one piece right in the middle that keeps the whole thing from collapsing that is called the key-stone. If a keystone species goes extinct then the rest of the ecosystem will crumble around it.
