Which one of the following is not a function of an ecosystem?

$A$: Niche becomes general and broader during biotic succession.
$R$: Species diversity increases but organic matter is decreased.

According to $David \ Tilman$,greater the diversity,greater is the primary productivity. Can you think of a very low diversity man-made ecosystem that has high productivity?

Choose the incorrect statement.

In a pond ecosystem,which organisms can occupy more than one trophic level?

Identify the mismatched event from the following structures.