Question

what are the main reason that account for the dwindling population of animals and plants on earth

Answer 1

Deforestation

Many species of wild animals and birds are endangered due to continuous poaching, even if it is illegal.

The pollution of the air and water also lead to the decrease in the numbers of wild plants and animals, which cannot survive in such polluted environment.

Answer 2

The main reason which accounts for decreasing population of plants & animals on the earth are habitat loss, deforestation and pollution.