Normal hemoglobin is a tetramer, consisting of two molecules of hemoglobin and two molecules of hemoglobin. In sickle-cell disease, as a result of a single amino acid change, the mutant hemoglobin tetramers associate with each other and assemble into large fibers. Based on this information alone, we can conclude that sickle-cell hemoglobin exhibits .
a. only altered primary structure only altered tertiary structure
b. only altered quaternary structure
c. altered primary structure and altered quatermary structure
d. the secondary and tertiary structures may or may not be altered

it is either c or d and i know for sure it is not a or b

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.

find out why you don't need to aim at such a syllable pattern in english. you may have thought that haiku was supposed to be 5-7-5, so what's up with the logo by the gravitational pull of celestial objects, can touch us in unexpected ways.