Question

a trend among the main sequence stars is the-
the hotter the star, the more brightly it burns
stars dimmer than the sun are of class o or b
most of the stars are white or red
the larger stars emit light that is blue

Explanation:

The Hertzsprung - Russell (H - R) Diagram shows that for Main Sequence Stars, there is a relationship between temperature (related to spectral class) and luminosity. Hotter stars (higher temperature) have higher luminosity (burn more brightly). Class O and B stars are among the hottest and most luminous. Stars dimmer than the Sun are not Class O or B (Class O and B are bright). Most stars on the Main Sequence are not just white or red (there is a range of colors). Larger stars (on the Main Sequence) are hotter (blue - white) but it's the temperature - luminosity relationship that is a key trend. The statement "the hotter the star, the more brightly it burns" aligns with the Main Sequence trend on the H - R Diagram.

Answer:

the hotter the star, the more brightly it burns