List two man-made ecosystems.

The most important compound which accounts for almost $80\%$ of the total depletion of the ozone layer is $.........$

What is meant by biological magnification?

Non-biodegradable materials do not break down by the action of microorganisms. Will there be any effect of heat and pressure if they remain buried under the land for a long time?

Why are non-biodegradable substances not broken down by microbes?

In a certain study conducted on the occurrence of $DDT$ along food chains in an ecosystem,the concentration of $DDT$ in grass was found to be $0.5\, ppm$ (parts per million),in sheep it was $2\, ppm$,and in man it was $10\, ppm$. Why was the concentration of $DDT$ maximum in the case of man?