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.

white blood cells or wbc s are mainly 2 types-

1.agranulocytes

2.granulocytes

the monocytes or macrophages of agranulocytes , dendritic cells which are accessory leucocytes, and b cells which is one type of lymphocytes   identify the antigens present on the pathogen's surface. these three cells are called antigen presenting cells(apc) which are phagocytes and destroy the antigens by secreting antitoxins. besides this leukocyte is always plays vital role in the immunity of the body.