Which of the following is required for the process of evolution by natural selection to occur? a) There must be a sudden change in some aspect of the population's environment.
b) In the population, there must be one or more traits for which individuals differ.
c) There must be a predator species that preys on individuals in the population.
d) The population must have recently been introduced to the region.

b) In the population, there must be one or more traits for which individuals differ.

Explanation:

Natural selection refers to the differential process of survival and reproduction caused by phenotypic differences among individuals in particular environmental conditions. These phenotypic differences are due to genetic variation among individuals, which is the primary source on which the natural selection act. In consequence, natural selection is composed of three main components: 1-variation among individuals, 2-inheritance of the phenotypic traits that vary within a population or species, and 3- different survival and reproduction.