Characters such as height, weight, and skin color are controlled by many genes acting together. these are examples of:

Are examples of quantitative trait / polygenic inheritance.

A quantitative trait is a phenotype that can be measured and depends on the cumulative actions of many genes and the environment.
These traits are very variable among individuals, there is a range of phenotypes with continuous distribution. For examples: height, weight, shoe size and skin color.

Exposure to solar flares would be the correct answer