Lungs serve the purpose of gas exchange. We inhale air, drawing in oxygen (O2) and exhale air, expelling carbon dioxide (CO2). Both of these molecules are small and nonpolar, and therefore freely pass though membrane bilayers of cells in the lungs. Based on this information, the movement of O2 from the alveoli of the lungs into the bloodstream is an example of

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.