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.

Ithink the dna sequences may vary but the amino acid sequences are identical. 

Interacting group of various species in a common location. for example, a forest of trees and undergrowth plants, inhabited by animals and rooted in soil containing bacteria and fungi, constitutes a biological community.

1) the mayans built pyramids just like the egyptians. the mayans also used hieroglyphics like them.2) power was passed down by family. for example, if the father dies, the son would be the next king.3)they both built pyramids for their structures.4)the main crop for the mayans was maize.5)they also grew manioc, beans,  squash,  amaranth, and chile peppers.

D. pray lands grasslands swamps