What happens to the force of gravity between two objects as they move farther away from each other?

The gravity they have stays the same all the time unless their mass decreases, but they have less gravitational force on each other as they move apart.

i think its c. amphipod

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.