( ( Discuss ( ( the effects ) ( of ( exercise ( on ( ( ( nervous and ) muscle ) tissue ) ) ) ) ) ) . )
(ROOT (NP (NP (NNS Discuss)) (NP (NP (DT the) (NNS effects)) (PP (IN of) (NP (NP (NN exercise)) (PP (IN on) (NP (ADJP (JJ nervous) (CC and) (JJ muscle)) (NN tissue)))))) (. .)))
Discuss the effects of exercise  on nervous and muscle tissue.
(ROOT (S (NP (JJ Only) (NNS animals)) (VP (VBP have) (NP (NP (NN muscle) (NN tissue)) (CC and) (NP (JJ nervous) (NN tissue)))) (. .)))
Only animals have muscle tissue and nervous tissue.