$...A...$ 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 $\mathrm{B}$

Which of the following food chain may not be directly dependent upon solar energy

Source of energy in an ecosystem is

In an ecosystem bacteria are considered as

Name any two organisms which can occupy more than one trophic level in an ecosystem.

In a terrestial ecosystem such as forest, maximum energy is in which trophic level