Answer:
C. top soil has more organic matter.
Explanation:
It's more fertile than subsoil, due to having more organic matter and because fertilizers are usually added to the topsoil only.
The correct answer is a dichotomous key. Basically, you use the key to decide what species an organism is by looking at what traits it has, and if it doesn't have some traits you can instantly rule out a large number of species which brings you closer to your answer of what the species is that you're looking at.
An under water volcano is called a submarine valcano
Don't trust me on this one, but i'll say d.
