Which structure the organism movea: cell wall b: flagellumc: cell membrane

B. Flagellum

a slender threadlike structure, especially a microscopic appendage that enables many protozoa, bacteria, spermatozoa, etc. to swim.

flagellum

Explanation:

its the cells apendage that helps it move.

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.

sodium i think the chemical element of atomic number 11, a soft silver-white reactive metal of the alkali metal group.