What findings led geneticists to postulate the multiple-factor hypothesis that invoked the idea of additive alleles to explain inheritance patterns? Mendel's experiment results involving flower pigmentation of pea plants showed that a number of additive alleles could explain continuous variation. Experimental results involving pigmentation in wheat showed that a number of additive alleles acting in Mendelian fashion could explain continuous variation Experimental results involving Drosophila eye color mutations showed that a O number of additive alleles acting in Mendelian fashion could explain continuous variation. Incomplete dominance shown in the experiment of crossing red and white colored snapdragon plants could explain continuous variation