Igneous rocks that are dense and dark-colored thet form from magma that is rich in iron and magnesium and poor in silica

light-colored, silica-rich igneous rock that is less dense than basaltic rock. dense, dark-colored igneous rock formed from magma;rich in magnesium and iron and poor in silica. Describes magma or igneous rock that is rich in feldspars and silica and that is generally light in color.

b i think it’s a water wheel turning in a stream

the objects have the same charge.