How did early settlers of North America change the environment to make it easier to travel and trade goods? A. They built a vast network of rail lines.
B. They carved tunnels to pass through mountains.
C. They cleared trees to build roads.
D. They dammed streams to create reservoirs.

D. They dammed streams to create reservoirs

Explanation:

Lewis and Clark (first inhabitants) did it

Columbus did it

Sacajewya did it

a.

Explanation:

no statements but ok.

the statement that best describes the idea of manifest destiny that was used in the 19th century would be that "it was fate that the united states would continue to  expand westward," since people thought the us was "destined" to do so. 

a social contract.

"a social contract is an agreement between citizens and their leader where the citizens give up certain freedoms in exchange for protection. the constitution of the united states is an example of a social contract."