Answer:
On the earth ,living and non-living organism is present.Living organism like human,animal,trees etc.Non living organism like air ,soil,water etc.
In the living world there exits a diversity of living organism.Due to availability of water and other things on the earth, human or animal can spend life.That is why earth is called living world.
On the other hand ,life is not possible on the Mars currently.There is a lack of water, which makes of building block and energy source for power,that is why life is not possible on Mars.But lots of scientist are studying about Mars and exploring about the existence of life on mars.
