Fact 1: Contact between rocks over long periods of time causes rocks to smooth. Fact 2: Rocks on the streambed are subrounded and fairly smooth. Given the two facts above, contact between rocks over long periods of time causes rocks to be what?
Choose from:
(A). coiled.
(B). homogenous.
(C). inactive.
(D). subrounded.
(E). dormant state.
(F). barrel-shaped.
(G). erosion.
(H). threatened.
Answer:
(D).