Large cells are difficult to maintain. How do cells overcome this problem?

They undergo cell division.

Explanation:

This is a good way to overcome the problem to be too big, because, in this way the cell is going to have more components and surface area of the cell stays the same.

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.

answer: substrate concentration. enzymes work best when there is a high enough substrate concentration for the reaction they catalyse.