Skin cells have terminally differentiated.

continually replicate.

become senescent quickly.

become quiescent quickly.

Continually Replicate.

Explanation: The epidermis (upper skin layer) constantly relace themselves.

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.

satellites are frequently used to make observations of the orbit on earth