Specific characteristics that vary among individuals

Specific characteristic that vary among  individuals is traits.

Explanation:

The difference between two individuals  are some how enduring psychological characters which makes the people different from one another, this tells us the differences of individuals. There are different types of traits like, intelligence, personality as well as the value trait. This includes the temperament, individual attitude, thoughts, belief, behavior and also character. Hence, thoughts, belief and personality are the characters of people in which this things reflect while communicating.

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

a and c are the answeres