changes in the environment could influence gene expression.
Explanation:
In humans, <u>skin color is defined by the abundance of "melanin" pigment</u>. The <u>darker is skin</u>, <u>high pigmentation</u> is there. Studies have proven that <u>high temperature</u> is the major reason for <u>high pigmentation/darker skin</u>. This is due to the reason that <u>high temperature</u> leads to the <u>increased expression</u> of the specific pigmentation related <u>genes</u> (e.g. MC1R gene). So, if a human is exposed to high temperature for a longer period, the action (expression) of the MC1R gene will be high as well. This will result in a tanned skin color. This is the reason that those <u>humans who live near to the equator (warmer climate) </u>have <u>darker skin</u> whereas those <u>humans that live close to poles (cold climate) </u>have <u>light-colored skin</u>.
I think the answer is {b.false} Infectious diseases are diseases that spread from one person to other either directly or indirectly. I think this is the answer.