Fill in the Blank Questions 32.The bones of vertebrate forelimbs are similar because of descent from a common ancestor. These forelimbs can be called __________________ structures. 33.During fossilization, remains of an organism may become suspended in fossilized plant sap, which is called ________. 34.Two closely related species that fail to recognize the courtship behavior of each other are said to be _________________ isolated. 35.Bats, pterosaurs, and birds are examples of _________ evolution. 36.A human example of stabilizing selection is _____________________. Â Â