Which is the primary colonizer in primary succession on rock?

Distinguish between:
$(a)$ Grazing food chain and detritus food chain
$(b)$ Production and decomposition

Which of the following characteristics can be observed in ecological succession?

Fill in the blanks.
$(a)$ Plants are called as . . . . . . because they fix carbon dioxide.
$(b)$ In an ecosystem dominated by trees,the pyramid (of numbers) is . . . . . . type.
$(c)$ In aquatic ecosystems,the limiting factor for the productivity is . . . . . . .
$(d)$ Common detritivores in our ecosystem are . . . . . . .
$(e)$ The major reservoir of carbon on earth is . . . . . . .

Which is the correct sequence in the food chain in a grassland?

Name an omnivore which occurs in both grazing food chain and the decomposer food chain.