Why would a researcher use a secondary source instead of a primary source when analyzing historical event

Why did the federal government choose to give each tribal member a 25-year deed to the reservation land? this was the life expectancy of native americans at this time, and the government wished to grant rights for only a single generation. they considered this to be enough time to keep the area calm before they could take the land back again for sale. the united states government believed that the nutrients from the land would be depleted by the end of the deed. the government believed this would be enough time for the tribal members to become self-reliant and adapt to the farming lifestyle.

How did the united states obtained the purchase of floridia to extand its frontiers to the pacific ocean

What is the evidence that depression can be linked to genetic as well as environmental factors? a. all individuals in similar stressful environments do not experience depression. b. all individuals with the gene variation tied to depression do not experience depression. c. individuals with a combination of environmental stress and gene variation are more likely to experience depression d. all of the above select the best answer from the choices provided оа 0 0 0