* Carbon Dioxide (CO2): 95.32%

* Nitrogen (N2): 2.7%

* Argon (Ar): 1.6%

The remaining 0.38% is a trace of other gases, including:

* Oxygen (O2): 0.13%

* Carbon Monoxide (CO): 0.06%

* Water Vapor (H2O): Variable, but generally less than 0.03%

* Neon (Ne): 0.00025%

* Krypton (Kr): 0.00003%

* Xenon (Xe): 0.000008%

* Methane (CH4): Traces

* Other gases: Traces

Key Features:

* Thin Atmosphere: Mars has a very thin atmosphere, with a pressure at the surface about 100 times thinner than Earth's.

* Low Gravity: The weak gravity of Mars means the atmosphere is easily lost to space.

* Cold Temperatures: The average temperature on Mars is about -63°C (-81°F), with extreme variations between day and night.

* Dust Storms: Mars is prone to massive dust storms that can engulf the entire planet.

* Variable Water Vapor: The amount of water vapor in the atmosphere is highly variable, depending on the season and location.

Significance:

* Climate Change: The composition of Mars's atmosphere has changed significantly over time, likely due to loss of gases to space.

* Habitability: The thin and cold atmosphere makes Mars unsuitable for liquid water on the surface, although evidence suggests it may have been different in the past.

* Exploration: Understanding the atmosphere of Mars is crucial for planning future missions to the planet, including the possibility of human exploration.