Which type of macromolecule can have a structure like the one in the picture? a. carbohydrate b. lipid c. nucleotide d. protein

That would a protein. Depending on the level of knowledge you need to know, that molecule is made of alpha helices and beta pleated sheets.

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.