What happens to skin color when there is an increase in blood flow?

When there is an increase in blood flow to the skin, the skin typically appears redder. This phenomenon is primarily due to the dilation of blood vessels, which allows more blood to flow closer to the surface of the skin. The increased oxygen-rich blood gives the skin a flushed or reddened appearance. This response can be seen during physical exercise, when a person is embarrassed, or in reaction to heat, where the body tries to cool itself by increasing blood flow to the surface.

In contrast, options suggesting that the skin becomes darker, remains the same, or appears yellower do not accurately reflect this physiological response to increased blood flow. Darkening of the skin is more associated with other factors, such as sun exposure or pigmentation changes, while a yellowish appearance may indicate certain medical conditions but is not a direct result of increased blood flow.