In 1968 a couple accused a hospital of switching their baby with another. DNA fingerprinting did not exist at this time so the hospital traced the blood types of the family in order to determine if a mistake was made. The mother had type A blood the father had type AB blood and the baby had type O blood

Based on the observation that only male crickets produce a song, you hypothesize that a male's song is a form of communication to potential mates. you set up a simple experiment to test this hypothesis. in the laboratory, you place a male snowy tree cricket in enclosure a, which is adjacent to enclosureb. in enclosure b, you place other insects, one at a time, and observe their responses to the male's song. the enclosures are designed so that the two insects being tested cannot see or smell each other, but sound is transmitted from enclosure a to enclosureb.