( ( ( ( ( ( Most ( of them ) ) ( are ( ( food , ) ( many ( are ( ( ( siblings and ) cousins ) ( like yourself ) ) ) ) ) ) ) , ) and ) ( ( a few ) ( are predators ) ) ) . )
(ROOT (S (S (NP (NP (JJS Most)) (PP (IN of) (NP (PRP them)))) (VP (VBP are) (NP (NP (NN food)) (, ,) (SBAR (WHNP (DT many)) (S (VP (VBP are) (NP (NP (NNS siblings) (CC and) (NNS cousins)) (PP (IN like) (NP (PRP yourself)))))))))) (, ,) (CC and) (S (NP (DT a) (JJ few)) (VP (VBP are) (NP (NNS predators)))) (. .)))
Most of them are food, many are siblings and cousins like yourself, and a few are predators.
(ROOT (S (NP (DT A) (JJR fewer) (NNS predators)) (VP (VBZ is) (ADJP (RBS most) (JJ likely) (S (VP (TO to) (VP (VB cause) (NP (NP (DT the) (NN number)) (PP (IN of) (NP (NP (NNS rabbits)) (VP (VBG living) (PP (IN in) (NP (DT an) (NN area))) (S (VP (TO to) (VP (VB increase))))))))))))) (. .)))
A fewer predators is most likely to cause the number of rabbits living in an area to increase.