( ( ( Describe differences ) ( among ( minerals ( , ( rocks ( , ( and soils ) ) ) ) ) ) ) . )
(ROOT (S (VP (VB Describe) (NP (NNS differences)) (PP (IN among) (NP (NNS minerals) (, ,) (NNS rocks) (, ,) (CC and) (NNS soils)))) (. .)))
Describe differences among minerals, rocks, and soils.
(ROOT (S (NP (DT A) (NN mineral)) (VP (VBZ is) (VP (VBN described) (PP (IN as) (NP (NP (DT a) (JJ natural) (NN substance)) (SBAR (WHNP (WDT that)) (S (VP (VBZ makes) (PRT (RP up)) (NP (NNS rocks))))))))) (. .)))