However, scientists still find it hard to assimilate this kind of trait to humans and the reason behind it is fairly simple: we humans live under a completely different environment compared to those animals that possess the negligible senescence trait.

Please remove spaces between words.
However,scientistsstillfindithardtoassimilatethiskindoftraittohumansandthereasonbehinditisfairlysimple:wehumansliveunderacompletelydifferentenvironmentcomparedtothoseanimalsthatpossessthenegligiblesenescencetrait.