The refers to the placement of fossils throughout the surface layers of the earth. transition record fossil record transition zone fossil accretion

In the text this question was provided for, you should be able to find the passage, "The fossil record refers to the placement of fossils throughout the surface layers of the Earth. Older fossils are buried more deeply than younger ones. The fossil record is life’s evolutionary epic that unfolded over four billion years as environmental conditions and genetic potential interacted in accordance with natural selection."

Fossil Record

a tetrad is the foursome during meiosis made by two homologous chromosomes that have each already replicated into a pair of sister chromatids.