What was discovered that provides evidence of a cause-and-effect relationship between the number of wire coils on an electromagnet and magnetic fields.

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.

i might be wrong but i think its a. let me know if i’m right and have a good rest of your day!