Why is evolution by natural selection called a theory? A. It is an educated guess about how organisms have changed over
time.
B. Scientists use it to describe how organisms have changed over
time.
C. It is an explanation that is well supported by scientific evidence.
D. Darwin reached his opinion after carefully considering
experimental data.

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?