The local water cycle involves which of the following?

The number of organisms present at any trophic level in an ecosystem depends on which of the following factors?

What is the amount of $PAR$ in incident solar radiation?

Given below is a list of autotrophs and heterotrophs. With your knowledge about food chain,establish various linkages between the organisms on the principle of 'eating and being eaten'. What is this inter-linkage established known as?
Algae,hydrilla,grasshopper,rat,squirrel,crow,maize plant,deer,rabbit,lizard,wolf,snake,peacock,phytoplankton,crustaceans,whale,tiger,lion,sparrow,duck,crane,cockroach,spider,toad,fish,leopard,elephant,goat,nymphae,spirogyra.

The trophic level of a lion in a forest ecosystem is:

Why do submerged plants receive weaker illumination than exposed floating plants in a lake?