Genetics is defined as
a. the branch of biology that deals with functions such as metabolism, respiration, and reproduction, rather than with structures
b. the science of inherited traits
c. the study of behavior and mental processes
d. the study of the changes that occur in people as they age, from conception until death.

The correct answer is B. The science of inherited traits

Explanation:

Genetics refers to the field in biology that focuses on studying genes which are the basic units of heredity and therefore the ones that determine inherited traits. Indeed genetic study the way traits are passed through reproduction and also the way genes change over time or express which is closely connected to evolution. Additionally, genetics have been widely studied beginning by the works of Mendel during the 19th century and nowadays the knowledge about genes including the behavior, function, and structure of them is broad. According to this, genetics is defined as the science of inherited traits.

in 1859, charles darwin set out his theory of evolution by natural selection as an explanation for adaptation and speciation. he defined natural selection as the "principle by which each slight variation [of a trait], if useful, is preserved".