Most plant roots grow in the
a. a horizon
c. c horizon
b. b horizon
d. d horizon

I believe the answer is A horizon. A soil horizon is a layer parallel to the soil surface, Whose physical characteristics differ from the layers above and beneath. Each soil type usually has three or four horizons which are defined by the physical features, chiefly color and texture. O Horizon; the top, organic layer of soil, made up mostly of leaf litter and humus. A horizon- the layer called topsoil; it is found below the O horizon and above the E horizon. Seeds germinate and plant roots grow in this dark-colored layer.

A