Question

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 —
f average temperature
g day length
h annual precipitation
j soil depth

Explanation:

Ecological succession involves the change in species composition over time, and soil depth is related to the development of an ecosystem. Average temperature (F), day length (G), and annual precipitation (H) are more related to climate and not direct indicators of succession. As the island develops, soil depth changes as organisms colonize and contribute to soil formation.

Answer:

J. soil depth