Ans. Although Mars has an atmosphere, it is very different from the Earth. Mars is smaller than Earth in diameter. This results in lower force of gravity — only about one- third of the gravity of Earth and a thin atmosphere with a pressure of 1% that of the Earth.
The Martian atmosphere is mainly composed of carbon dioxide (95.3%), nitrogen (2.7%) and argon (1.6%). There is only a small amount of oxygen (0.13%) and water vapour (0.03%). In comparison, Earth atmosphere has 77% nitrogen, 21% oxygen, 1% argon, 0.038% carbon dioxide and 1.0% water vapour.
Further, due to such a vast difference in atmosphere, the surface temperature of the Mars is about –63°C whereas that of Earth is 14°C.