Here's why:
* Venus: Its atmosphere is primarily composed of carbon dioxide (CO2), with nitrogen (N2) as a secondary component. It also has trace amounts of other gases like sulfur dioxide (SO2) and argon (Ar).
* Mars: While its atmosphere is much thinner than Venus, it also consists mainly of carbon dioxide (CO2), with nitrogen (N2) as the second most abundant component. It has smaller amounts of argon (Ar) and trace amounts of other gases like oxygen (O2) and water vapor (H2O).
While both planets share a dominant composition of CO2 and N2, their atmospheric pressures and overall densities are vastly different. Venus has a thick, dense atmosphere, while Mars has a thin, wispy one.
It's worth noting that Earth's atmosphere is vastly different, dominated by nitrogen (N2) and oxygen (O2), making it unique among the terrestrial planets.
