A researcher is studying three wolf packs that hunt in the same area. The first pack preferentially kills mature, healthy moose; the second pack preferentially kills sick, old moose; and the third pack tends to kill an equal number of healthy and sick moose. Which pack likely plays the greatest role in determining the birth rate of the moose population

sheep is a herbivore animal whereas grasshopper belongs to the class chordates but both of them feed on greens.  

if grasshopper and sheep feeding on a pasture land, i do not think both of them will have any impact on each other. however, the number of the species can make difference. since sheep feed on greens, there is a possibility there left no pasture land for the grasshoppers or they may get extinct.