After asking a question, a scientist can form a(n) is an idea that may be proved or disproved by an experiment.

Hypothesis -  it can then be tested to examine if it is correct or false and why

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.

other information encoded in your genes might distinguish you from the others in the group