Why did many canals run east-west

the parallel lines that run from east to west on a map show lines of longitude

Explanation:

latitude specifies the north-south position of a point on the earth's surface

after the spaniards introduced horses to plains native americans, the lives of the tribes changed. tribes became less settled and sedentary. the horse allowed them to hunt animals such as bison or buffalo, and, instead of staying in one place, tribes began to be nomadic.