( ( ( ( ( Mass wasting ) ( is ( ( the name ) ( given ( to ( erosion ( due ( to gravity ) ) ) ) ) ) ) ) -- ) ( this ( ( is , ) ( when ( ( ( ( ( ( rocks , ) soil ) , ) or ) dirt ) ( ( moves downhill ) ( under ( ( the influence ) ( of gravity ) ) ) ) ) ) ) ) ) . )
(ROOT (S (S (NP (NNP Mass) (NNP wasting)) (VP (VBZ is) (NP (NP (DT the) (NN name)) (PP (VBN given) (PP (TO to) (NP (NP (NN erosion)) (ADJP (JJ due) (PP (TO to) (NP (NN gravity)))))))))) (: --) (S (NP (DT this)) (VP (VBZ is) (, ,) (SBAR (WHADVP (WRB when)) (S (NP (NP (NNS rocks)) (, ,) (NP (NN soil)) (, ,) (CC or) (NP (NN dirt))) (VP (VBZ moves) (ADVP (RB downhill)) (PP (IN under) (NP (NP (DT the) (NN influence)) (PP (IN of) (NP (NN gravity)))))))))) (. .)))
Mass wasting is the name given to erosion due to gravity--this is, when rocks, soil, or dirt moves downhill under the influence of gravity.
(ROOT (S (NP (NNP Gravity)) (VP (VBZ causes) (S (NP (NNS rocks)) (VP (TO to) (VP (VB roll) (ADVP (RB downhill)))))) (. .)))