Pisaster is a . . . . . . .

In a food chain, which of the following is produced in the largest amount?

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?

Succession on a secondary bare area is known as:

Match Column-$I$ with Column-$II$. Select the option with the correct combination.

$1$. Standing state	$p$. Mass of living material at a given time
$2$. Pioneer species	$q$. Amount of nutrients in the soil at a given time
$3$. Detritivores	$r$. Species that invade a bare area
$4$. Standing crop	$s$. Breakdown detritus into smaller particles

Secondary producers are