Why does Gene, against his better judgement, jump from the tree? In your opinion, dose this show Gene to be strong or weak? Explain.

Peer pressure. Everyone else is jumping, so Gene does too, much to Finny's encouraging and persuasion. Gene, at this point in the novel, is easily influenced, and in some respects is still "finding himself." I don't think it necessarily means he is weak, but rather, human. In the absence of Finny, Gene later finds himself and his own opinions and personality, and grows the backbone he so sorely needs in the beginning of this novel.