How much percentage of absorbed water is used in photosynthesis

$...A...$ is required for higher primary productivity. $...B...$ have the lowest primary productivity as the soil is deficient in moisture.

Choose the correct option for $\mathrm{A}$ and $\mathrm{B}$

If a single plant species is removed from a food web, then most likely

Which one of the following types of organisms occupy more than one trophic level in a pond ecosystem?

A wolf has just eaten a lamb when tiger saw the wolf attacked it and consumed it. The tiger is in ecological terms

Flow of energy through various trophic levels in an ecosystem is unidirectional and non-cyclic. Explain.