6. The decline of the long drive and the cattle boom resulted from

a. the settlement of homesteading farmers on range land.

b. a series of extraordinarily severe winters.

c. overgrazing and overproduction.

d. the inability to recruit enough veteran cowboys.

e. barbed-wire fencing.

Answer: A. the settlement of homesteading farmers on rangeland,

B. a series of extraordinarily severe winters,

C. overgrazing and overproduction, E. barbed-wire fencing

Explanation: Ranchers kept track of their cattle through earmarks and, later, brands. Wanting to protect their own herds, ranchers and farmers began fencing off their land with barbed wire to keep the cattle from roaming. This way they could keep track of their own cattle and ensure their land didn't become overgrazed.

the settlement of homesteading farmers on range land

Explanation:

The decline of the long drive and the cattle boom resulted from the settlement of homesteading farmers on range land; a series of extraordinarily severe winters; overgrazing and overproduction; and barbed-wire fencing.