Differences in traits such as hair texture are determined by differences in

 genes or genetic traits. These genes determine what physical characteristics a human will possess. They are determined by the parents of an offspring and vary from person to person

Explanation:

relative humidity, temperature and dew point -- are bound together in the mathematical relationship below. relative humidity changes when temperatures change. because warm air can hold more water vapor than cool air, relative humidity falls when the temperature rises if no moisture is added to the air. so i would say a

weathering is the answer.