Question

How are the earth's principal biological systems being depleted?

Answer 1

it can be deleted as
the increase in green house gases(sulphur dioxide carbon dioxide ) which doesn't allow heat to reflect
which causes increase in surface temperature
and it causes flood in coastline and rise in temperature

Answer 2

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The earth’s principal biological systems are being depleted by excessive use. Over . fishing is quite common. Forests are being cut to obtain firewood for cooking. Grasslands are turning into barren wastelands and croplands are deteriorating as their productivity has been impaired.