What does the cardiovascular system do?

carries hormones for the endocrine system
transports oxygen and carbon dioxide for the respiratory system
sends nerve impulses to the brain and spinal cord
carries nutrients for the digestive system
works with the immune system to fight infection

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.