Two new planets were recently discovered. Each planet orbits a different star. In many ways, both the planets and the stars are very similar: Both planets are about the same size.
Both planets are about the same distance from their star.
Both stars are about the same surface temperature.
Both stars are about the same brightness.

However, astronomers also have evidence that shows that the atmospheres of the two planets are different:
Planet A has a thin atmosphere with little carbon dioxide or methane.
Planet B has a dense atmosphere that is high in carbon dioxide and methane.

Using only the information provided above, make a claim as to which planet is likely to be warmer on average. Then, complete your scientific explanation by supporting your claim with evidence and reasoning