Final answer:
Nose shape and skin color in humans are influenced by environmental factors like sun exposure and genetic adaptations, as well as cultural factors through sexual selection.
Step-by-step explanation:
Nose shape and skin color are two physical traits in humans that have been influenced by genetics and environmental factors. One significant environmental influence is sun exposure, which affects the level of melanin in the skin, with darker skin evolving in places with more intense ultraviolet rays to protect against sun damage. This evolutionary adaptation, known as directional selection, is why regions closer to the equator have populations with darker skin pigmentation.
On the other hand, areas with less sunlight may favor lighter skin, which facilitates vitamin D production. In addition to environmental pressures, cultural factors also contribute to the evolution of traits through sexual selection. This means that ideas of beauty and attractiveness, which can vary widely between cultures and have changed over time, may also influence the physical characteristics of a population.