What action by an individual person is most likely to have a positive impact on an ecosystem?
OA
planting pine trees to be sold as Christmas trees on private land
planting native plants in a vacant lot
planting a single economically valuable crop on 30 acres of land
OD
planting exotic shrubs in a community park

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.