Tick the correct answer.

(i) Which is not a natural ecosystem?

(a ) Desert

(b ) Aquarium

(c ) Forest

(ii ) Which is not a component of human environment?

(a ) Land

(b ) Religion

(c ) Community

(iii ) Which is a human-made environment?

(a ) Mountain

(b) Sea

(c) Road

(iv ) Which is a threat to environment?

(a) Growing plant

(b) Growing population

(c) Growing crops