Which main-sequence on the hertzsprung-russell diagram are the least massive? a.) yellow b.) blue c.) orange d.) red

D.) Red

Explanation:

A star's luminosity and surface temperature are its two most important observational properties and are related to its mass in the formation. A graph of luminosity against temperature produces the Herzprung-Russell Diagram. Its historical importance arises, not only because it allowed the observation that stars evolve, but because they have become extremely important in the study of stellar evolution.

This diagram owes its name to two astronomers: the Danish Ejnar Hertzsprung and the American Henry Norris Russell, who, independently, in 1911 found that in a diagram of this type the stars did not occupy a random position, but were mostly located in certain positions, according to its mass and its radius.

According to this diagram, the least massive sequence is that of red color.

the second type of galaxy is called a barred spiral, which has a thing called a bar straddling the nucleus