* Carbon dioxide (CO2): This makes up a whopping 95% of the atmosphere.

* Nitrogen (N2): This accounts for about 2.7% of the atmosphere.

* Argon (Ar): This makes up about 1.6% of the atmosphere.

There are also trace amounts of other gases, including:

* Oxygen (O2): This is present in very small amounts, less than 0.1%.

* Carbon monoxide (CO): This is also present in very small amounts.

* Water vapor (H2O): The amount of water vapor varies significantly, but it's generally very low.

* Methane (CH4): This is a very rare gas, but it's interesting because it could be a sign of past or present life.

It's important to note that the Martian atmosphere is much thinner than Earth's, with a pressure at the surface that's about 100 times lower than Earth's atmospheric pressure. This means that the atmosphere on Mars provides very little protection from the Sun's radiation.