If the plant morphs you study are going to respond to natural selection, they much vary in phenotype, and this variation must be heritable. this variation must also result in differences in relative fitness among the morphs. for example, the size of leaves a plant produces could affect relative fitness by determining how much energy a particular plant collects. the amount of energy collected would affect investment in reproduction. leaf size is a measurable trait. below, suggest three other measurable plant traits that could affect relative fitness and explain them briefly.: