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 . 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 . altered primary structure and altered quaternary structure; the secondary and tertiary structures may or may not be altered only altered tertiary structure only altered quaternary structure only altered primary structure

The correct answer is - altered primary and quaternary structure; secondary and  tertiary structure may or may not be altered.

Explanation:

a) Primary structure: It is fundamentally the amino acid sequence or arrangments. Every protein has a remarkable amino acid sequence and little change in these sequence modifies the primary structure. On account of sickle cell, the amino corrosive has changed, and henceforth the essential structure of the protein molecule changes.  

b). secondary structure: It is the folding of the primary structure chain, which results from intermolecular and intramolecular hydrogen holding of the amide group. Ex; Alpha helix and beta sheets. In the above case, this may or might not have changed as there is no conclusive method to know this.  

c) Tertiary structure: Most proteins' tertiary structures are mixes of a-helices, b sheets, and circles and turns. Every protein has interesting three-dimensional structure, folded in a particular way now and then known as a domain. For our situation, since it depends on the optional structure, it might have changed.

d) Quaternary structure: It is the relationship of numerous individual protein chains into a solitary protein with various subunits. The subunits arrangment offers to ascend to a steady structure. For our situation, a hemoglobin tetramers partner with one another and gather into large fibers. This has changed the first structure and accordingly we state the quaternary structure has changed.