Technology can have good and bad effects. what is a bad effect of spraying pesticides on crops with the use of airplanes?
a. it is sometimes sprayed too far from the crops.
b. it increases food production.
c. it lowers the cost of food.
d. it decreases the cost of spraying pesticides.

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.