What are the constants (controlled variables)? Select all that apply. * 2
Number of daphnia
Heart rate of daphnia
Type of petri dish
Different concentrations of caffeine solution
Amount of liquid
✓ Type of microscope
Species of daphnia

Which statement about variation is true? a) all phenotypic variation is the result of genotypic variation.b) all genetic variation produces phenotypic variation.c) all nucleotide variability results in neutral variation.d) all new alleles are the result of nucleotide variability.e) all geographic variation results from the existence of clines.