In which process do animals turn food energy into a form their bodies can
use?

cellular respiration

Explanation:

when energy in food like proteins, carbs are converted into energy for the animals' cells

Hope this 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.

not always but somethings can be reproduced in a laboratory.