Final answer:
To estimate total phenotypic variance (Vp) from a graph or data, one uses the sum of genetic and environmental variances. This incorporates the influence of genetic structure and environmental factors on phenotypic variation in a population.
Step-by-step explanation:
When estimating Vp (total phenotypic variance) from a graph or presented data, the value used is d) the sum of genetic and environmental variances. Phenotypic variance in a population can be influenced by genetic structure, environment, diet composition, and many other factors. Genetic variance is specifically the fraction of phenotypic variation that is attributable to differences in genes among individuals in a population. Population genetics takes into account both genetic and environmental factors to explain phenotypic variation and is critical for understanding how populations evolve through natural selection, genetic drift, gene flow, and mutation.