Early civilizations modified the physical environment by creating irrigation systems and dams. what was the purpose of these modifications?

a to reduce the animal population

b to create more fertile land for growing crops

c to provide better defense for cities

d to allow for easier travel between cities

the right answer is the third one: turnpikes went short distances to connect markets. turnpikes, also known as toll roads, were very important for trade and transportation (of people, goods and products) in the 19th century, coinciding with the expansion towards the west. they contributed significantly to the economic development of the united states.

the spanish  

hope this meaning spain btw