Question

what would happen when natural resources exhausted

Answer 1

In case the natural resources were used up the most likely thing is that human beings would die.

You should the  role of forests is to clean the air we breathe, in case of lack of forests much much higher pollution to poison us.

Forests also provide habitat and food for animals and thus without forests people would die.

Water is also used to sustain life. And in case of no water, people are likely to suffer.

There is also the role of the fertile land which is used in the production of food.