Lava from an underwater volcano piles up over many years. Eventually, the pile of lava sticks up above the ocean surface, forming a new island. To show that succession is occurring on the island, it would be MOST helpful for a scientist to measure changes in:
A. average temperature
B. day length
C. annual precipitation
D. soil depth

Option (D)

Explanation:

In the given condition, the magma erupting from the underwater volcano forms lava and with more frequent eruption, it eventually piled up in such a way that it forms an island, whose surface lies above the sea surface or the ocean surface.

In order to study and demarcate that there occurs a succession in the island, the first step to be taken is by measuring the changes that occur in terms of soil depth. The height of this island can be measured vertically, and also the scientists can study how the sediments and the rocks comprising different minerals, varies from the bottom to the top layers.

Thus, the correct answer is option (D).

"a.) well–developed vascular system."

answer; both surfaces of the membrane are nonpermeable