The answer is B.
The Great Migration was the movement of six million African Americans from the Southern U.S. to the North. As you probably know, back in the 1900's, segregation of African Americans was on the rise. At the time, the North was not involved in this segregation, so African Americans migrated to the Northern states to escape discrimination.
Arms race hope that helped
D because cowboys ride horses not herds them and second they work on a ranch and I know that because I live on a ranch and herd cows
There are many of them but the most common are:
1.) Photosynthesis
2.) Solar Energy
3.)Thermochemical Reactions