An ecosystem resists change because it is in a state of

During ecological succession,how does the complexity of the ecosystem structure change?

Identify $Y$ and $Z$ from the given figure representing the carbon cycle.

Keystone species are

In a pond,we see plants which are free-floating; rooted-submerged; rooted-emergent; and rooted with floating leaves. Identify the type of plant for each of the following:

Plant Name	Type
$(1)$ Hydrilla	....................
$(2)$ Typha	....................
$(3)$ Nymphaea	....................
$(4)$ Lemna	....................
$(5)$ Vallisneria	....................

Which groups are organisms divided into based on their primary ecological role?