The end of the cattle boom a. had nothing to do with climate changes. b. was the result of increased competition for open range. c. was due entirely to the invention of barbed wire. d. happened when demand exceeded supply.

b. was the result of increased competition for open range.

Explanation:

“the battle of stalingrad is not a turning point necessarily in strategic terms, because a lot more has to be done before the soviets can be certain of defeating germany,” says renowned world war ii historian richard overy. the germans had fought nearly a thousand miles across the soviet union to get to stalingrad.

d. migration