Arthropods have an exoskeleton made of

What adaptation is apparent in the bodies of the three tortoise species shown in figure 16-2

What is the inability of an individual or a society to achieve a minimum standard of living known as ?

How can a geological time scale best be reconstructed? a) comparing vestigial structures in living species b) comparing homologous structures in living species c) examining homologous structures in fossil remains d) examining the written records of scientists from past cultures