Why did nixon order us forces to mine north vietnamese harbors in 1972?

To avoid the supplies to north vietnam.

Explanation:

Mr. president Richard Nixon  did announce an attack  during two week at the north of vietnam. it was in 1972.

The reason registered is that peace talk between the United States and North if Vietnam collapsed.

the answers is b.   environments.

2686-2181 bce-- "egyptian civilization developed along the nile river in large part because the river’s annual flooding ensured reliable, rich soil for growing crops."

1069-664 bce-- "ancient egyptians developed wide-reaching trade networks along the nile, in the red sea, and in the near east."