Which piece of scientific knowledge best supports the idea of the cell theory that cells come from existing cells? Cells are the smallest structures that carry out specialized functions in a living organism.
Chromosomes are copied during the replication process.
Multicellular organisms have chromosomes located in membrane-bound nuclei.
Some members of a species display a trait due to mutations in genetic coding.

Cells are the smallest structures that carry out specialized functions in a living organism.

they deliver oxygen to the blood

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.