Insecticides sprayed in low concentrations may increase the yield of a crop, but may also be harmful to wildlife. What is an explanation for this?

the choices;
a)Insecticides cause acid rain.
b) Insecticides enter the food chain
c) Insecticides increase the nitrates in the soil
d)Insecticides kill other plants.

During which phase does earth see more than half of the moon's surface? 1)first quarter2)third quarter3)waxing gibbous4)waning crescent

One of the reasons that stars are so large is because

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.