First order consumers are ...

The depletion of the ozone layer is a cause of concern. Why?

Write the appropriate names of the trophic levels $Z$ and $X$ in the figure given below.

Select the mismatched pair in the following and correct it.
$(a)$ Biomagnification — Accumulation of chemicals at the successive trophic levels of a food chain
$(b)$ Ecosystem — Biotic components of environment
$(c)$ Aquarium — $A$ man-made ecosystem
$(d)$ Parasites — Organisms which obtain food from other living organisms

Accumulation of harmful chemicals in our body can be avoided. Explain how this can be achieved.

In the following food chain,grass provides $4000 \ J$ of energy to the grasshopper. How much energy will be available to the snake and the frog? Grass $\rightarrow$ Grasshopper $\rightarrow$ Frog $\rightarrow$ Snake.