How is a scientific law different from a scientific theory? a. a theory becomes a law after a long period of time has passed. b. theory is why something happens and a law is how something happens. c. a theory cannot be disproved but a law can be disproved. d. a theory is used for biology and chemistry and a law is used for physics.

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.