Effects of johnson's pardon policy?

Why is it useful for historians to base certain studies on the analysis of historical periods

The first map shows colonial powers and their holdings (1945). the second map shows human development worldwide. compare the two maps. what do the maps indicate about regions that gained independence in the second half of the twentieth century? they differ in their development patterns. they are as developed as their colonial powers. they are more developed than their colonial powers. they remain less developed than their colonial powers.

To keep other european powers from threatening its empire in america, spain sent soldiers, settlers, and?