( they ( ( ( ( ( study ( shelter ( and ( house building ) ) ) ) , ) and ) ( experience ( ( the dependence ) ( of ( humans ( on ( ( plants and ) animals ) ) ) ) ) ) ) . ) )
(ROOT (S (NP (PRP they)) (VP (VP (VBP study) (NP (NN shelter) (CC and) (NN house) (NN building))) (, ,) (CC and) (VP (VBP experience) (NP (NP (DT the) (NN dependence)) (PP (IN of) (NP (NP (NNS humans)) (PP (IN on) (NP (NNS plants) (CC and) (NNS animals)))))))) (. .)))
they study shelter and house building, and experience the dependence of humans on plants and animals.
(ROOT (S (NP (JJ Many) (NNS animals)) (VP (VBP depend) (PP (IN on) (NP (NP (NNS plants)) (PP (IN for) (NP (NN shelter)))))) (. .)))
Many animals depend on plants for shelter.