Describe animal interactions that affect populations in the tundra ecosystem. (Please help please... I have already had a mental breakdown over school today because its getting harder and harder so please help!)

Herbivorous animals are unable to feed and end up migrating to other regions in search of food.

Explanation:

The tundra is a type of vegetation composed almost exclusively of mosses and lichens. This type of vegetation is found in regions with a polar climate. It is important to note that the tundra has a very fast vegetative cycle. That's because it freezes quickly and can be covered with ice all winter. This ends up modifying the lives of some animals that feed on this vegetation. These animals end up with unavailability of food and need to migrate to others in search of food.

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.