According to figure 25-2, is antares or vega hotter than the sun?

The star that is hotter than the Sun is Vega. This is due to the fact that Vega is much closer to the Main Sequence. In this part of the galaxy the temperature is much bigger, the density is also bigger, and the stars in this part have bigger temperatures and also densities, no matter the size of them.

Ithink a hope that

The correct answer is:   [b]:   "has no atmosphere" .