How is our atmosphere different from the atmospheres on Venus and Mars ?

Answer

On planets Venus and Mars, carbon dioxide the major component constituting upto 95-97% of the atmosphere. Nitrogen gas and oxygen gas are absent. Also, their respective atospheres do not have water vapour. No life is known to exist there. On the contraty, on earth, air form the blanket earth having nitrogen (78.08%), oxygen (20.94%), carbon dioxide (0.03%), argon (0.91%) and trece components (0.04%) It has life on it.