AP BIOLOGY

Detailed explanation-1: -To establish the age of a rock or a fossil, researchers use some type of clock to determine the date it was formed. Geologists commonly use radiometric dating methods, based on the natural radioactive decay of certain elements such as potassium and carbon, as reliable clocks to date ancient events.

Detailed explanation-2: -Using embryology, scientists can identify common ancestors through structures present only during development and not in the adult form. Biogeography offers further clues about evolutionary relationships. The presence of related organisms across continents indicates when these organisms may have evolved.

Detailed explanation-3: -Molecular similarities provide evidence for the shared ancestry of life. DNA sequence comparisons can show how different species are related.

Detailed explanation-4: -Anatomy. Species may share similar physical features because the feature was present in a common ancestor (homologous structures). Molecular biology. DNA and the genetic code reflect the shared ancestry of life.