Which of the following best explains why mars and Venus surface temperature is very despite both planets having S atmospheres that contain mostly carbon dioxide
The most accurate explanation for the difference in surface temperatures between Mars and Venus is the effect of their atmospheres' greenhouse gases. While both planets have atmospheres composed mostly of carbon dioxide (CO2), Venus has a significantly thicker atmosphere compared to Mars.
Venus has a thick, dense atmosphere consisting of around 96.5% carbon dioxide. This atmosphere traps heat effectively due to the greenhouse effect, in which greenhouse gases like CO2 trap infrared radiation from the Sun, preventing it from escaping back into space. As a result, the surface temperature of Venus reaches extremely high levels, averaging around 867 degrees Fahrenheit (464 degrees Celsius), making it hotter than Mercury, despite being farther away from the Sun.
In contrast, Mars has a thin atmosphere, with carbon dioxide making up around 95% of it. The thin atmosphere is not as capable of trapping heat as efficiently as Venus's thick atmosphere. Due to the lack of significant greenhouse gas effect on Mars, the average surface temperature remains much colder than Earth, with an average of -80 degrees Fahrenheit (-60 degrees Celsius).