Bottom dwelling animals constitute:

Two or more species occupying identical or overlapping areas are known as

Match the types of niche in Column-$I$ with their description in Column-$II$.

$i$. Habitat niche	$a$. In the absence of competition in the habitat
$ii$. Trophic niche	$b$. Position of organism in the environmental gradient
$iii$. Multidimensional niche	$c$. Physical space occupied by an organism
$iv$. Fundamental niche	$d$. Level of organism in the food chain

In desert grasslands,which type of animals are relatively more abundant?

How many of the following statements are correct about niche?
$i$. It denotes the functional role played by an organism.
$ii$. It deals with the flow of energy from one organism to another.
$iii$. As soon as a niche is left vacant,other organisms fill that position.
$iv$. The same niche is shared by two or more species.
$v$. Organisms living in the same habitat differ in their niches.

Match the following adaptations in Column $I$ with the respective organisms in Column $II$.

Column $I$	Column $II$
$i$. Thick cuticle on leaf surface	$a$. Desert lizards
$ii$. Leaves reduced to spines	$b$. Archaebacteria
$iii$. Burrow into sand to escape from heat	$c$. Desert plants
$iv$. Hot springs	$d$. Opuntia