When can natural selection lead to evolution in a population?
A. If the environment of the population is stable and provides
resources
B. If the individuals in the population have very little genetic variation
C. If the population has unequal numbers of parents and offspring
D. If the frequency of the alleles for a trait in the population changes

The diagram below shows the layers of a rock having a trilobite: a rock column labeled rock is shown. the column has three layers. the bottommost layer of the rock has one shaded rhomboid shape, the middle layer has a rhombus with a diagonal along with two identical organisms marked as, trilobite, in the key, the top layer has two semicircles. a key is shown on the right side of the diagram. the shaded rhombus is marked as a, the rhombus with the diagonal is marked as b, the semicircle is marked as c which statement about the rock fossils is true?