The praying mantis is a good example of:

Statement-$I$: In the absence of predators,prey species population can decline and cause ecosystem instability.
Statement-$II$: Predators are prudent in nature and overexploit their prey.

Given below are two statements.
Statement $I$: $Calotropis$ growing in abandoned fields is never consumed by cattle and goats.
Statement $II$: $Calotropis$ produces highly poisonous cardiac glycosides.
In light of above statements,select the most appropriate answer from the option given below.

Barnacles growing on the back of a whale is an example of .........

There is more competition for survival between

Copepods are . . . . . . .