What is the the difference between a valley and a plain?​

is that plain is (rare|poetic) a lamentation or plain can be an expanse of land with relatively low relief while valley is an elongated depression between hills or mountains, often with a river flowing through it.

Explanation:

A valley is a low area of land between mountains or hills,commonly with water flowing through the bottom,and a plain is an wide expanse of flat land.

answer; eliminate parking problems in cities, because a car took up only half as much space as a horse and buggy;