This is because of the history of the region. The Europeans during their exploration (remember Christopher Columbus?) discovered this new continent and settled down. Farming was their main economic activity at the time. Because they needed cheap labor, they engaged in slavery by importing slaves from Africa to work on the farms. The interaction between the two races is attributed to the current race in South America. Native Americans due to their close proximity have also interacted with the races in these regions.
The protostar is a new star that is formed at the end of the Hayashi track and is luminosity temperature relationship of infant stars that are less than M 3. The protostar ends its period and becomes a Tauri star that is extremely luminous.
After which the main sequence of the stars are formed is the next stage in stellar evolution and is dependent on its mass like the sun after this period the star turn red as it has a hydrogen-rich core and it starts to branch out displaying extreme density.
The last stage is the white dwarf star as the star has degenerate and left is the exhaust core which is very dense.
