Question

buffalo population: 1800 to 1895
date | population
1800 | 40,000,000
1850 | 20,000,000
1865 | 15,000,000
1870 | 14,000,000
1875 | 1,000,000
1880 | 395,000
1885 | 20,000
1889 | 1,091
1895 | less than 1,000
source: u.s. department of interior (adapted)
a major impact of the trend shown on the chart (above) was that
○ frontier trading posts became more prosperous (made money)
○ plains indians lost their main source of food, shelter, and clothing
○ white settlers became dependent on buffalo products
○ reservations were relocated closer to buffalo migration routes

Explanation:

The chart shows a catastrophic decline in the buffalo population from 40,000,000 in 1800 to less than 1,000 by 1895. Plains Indians relied entirely on buffalo for food, shelter, clothing, and other essential resources, so this near-extinction eliminated their primary means of survival. The other options are incorrect: frontier trading posts would not prosper as buffalo disappeared, white settlers were not dependent on buffalo products, and reservations were not relocated closer to buffalo migration routes (in fact, settlers and policies displaced Indians and destroyed buffalo herds).

Answer:

Plains Indians lost their main source of food, shelter, and clothing