Final answer:
The presence of carbon dioxide in the Earth's atmosphere in the past had an impact on the average surface temperature, keeping it higher through the greenhouse effect.
Step-by-step explanation:
The subject of this question is Earth Science, specifically related to the Earth's atmosphere and its impact on the surface temperature. The question discusses the presence of carbon dioxide (CO2) in the atmosphere and how it affected the average surface temperature of the Earth in the past.
Before life was present on Earth, the atmosphere had a higher concentration of CO2, which resulted in a stronger greenhouse effect. The greenhouse effect is a natural process where certain gases, like CO2 and water vapor, trap heat radiated from the Earth's surface, keeping it warm.
This increased concentration of CO2 in the early atmosphere helped maintain a higher average surface temperature on Earth, despite the Sun emitting less energy at that time.