Which rock type is prevalent on lunar plains and is often darker in color?

Basalt is a volcanic rock that is indeed prevalent on the lunar plains, specifically in the maria, which are the large, dark, flat areas on the moon's surface. These basaltic plains formed from ancient volcanic activity and are rich in iron and magnesium, giving them a darker color compared to other rock types found on the moon, such as anorthosite, which is lighter and predominantly composed of plagioclase feldspar.

The presence of basalt represents significant geological processes, including the cooling and solidification of lava flows. This dark appearance is a result of the minerals present in basalt, which absorb more sunlight than lighter-colored rocks. Recognizing basalt's characteristics helps in understanding the moon's geological history and the processes that shaped its surface.