$A$ man-made ecosystem is:

$A$ snake feeds on a rat,a hawk feeds on the snake,and the rat feeds on a grasshopper. In this food chain,what is the trophic level of the rat?

Which of the following statements is incorrect regarding the phosphorus cycle?

In a food chain of a grassland ecosystem,the top consumers are

Match the columns:

Column-$I$	Column-$II$
$(i)$ Primary succession	$(i)$ Development of ecosystem
$(ii)$ Ecological succession	$(ii)$ Lichens
$(iii)$ Pioneer species on rocks	$(iii)$ Near to the equilibrium with the environment
$(iv)$ Climax community	$(iv)$ New species on bare environment

Which of the following animals occupies more than one trophic level in the same ecosystem at the same time?