Every living organism on earth is dependent on plants directly or indirectly. If plants are removed, herbivores will die as they are dependent on plants for food. If herbivores die then carnivores will die automatically as they are dependent on herbivores for food. So animal life will be adversely affected. Similarly due to lack of plants the amount of oxygen will be reduced on earth which will affect the breathing process which in turn reduces the chances of humans to survive on earth.