Hemoglobin is a protein found in the red blood cells of vertebrates and in the plasma of many invertebrates. The function of this protein is to transport oxygen throughout the body and to bring carbon dioxide back to be expelled from the organism. If the amino acid sequence of the protein is altered, the mutated protein is not as efficient at carrying oxygen as is the normal hemoglobin. Which argument is supported by this information? A. The mutated hemoglobin protein can still carry carbon dioxide to be expelled from the organism.

B. Hemoglobin must be a simple molecule because it is found in both vertebrates and invertebrates.

C. Structural changes of hemoglobin affect its ability to carry oxygen, indicating that the shape of a protein is important to its function.

D. Normal hemoglobin must be a larger molecule than the mutated hemoglobin since it has sufficient space to attach to and carry both oxygen molecules and carbon dioxide molecules.