How do doctors confirm a disease.
please tell fast.

They usually run tests too see. For example, that's why they made blood tests. They take you blood from you, and run tests to see if you have a disease.

Explanation: Hope it helps!

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.