what did the farmers build to bring water to their farming lands from rivers (in the Neolithic period)

Later people built canals to protect houses from flooding and move water to their fields. These ditches brought water to the fields. To protect their fields from flooding, farmers built up the banks of the Tigris and Euphrates. These built-up banks held back flood waters even when river levels were high

Explanation:

d.prevent the spread of communism outside of eastern europe.

the answer is title i subtitle b