Hemoglobin and myoglobin both differ in terms of their characteristics, specifically in their function and structure, so it wouldn't be appropriate to say that they both have all of the listed characteristics. However, based on the given list, the characteristic not shared by both hemoglobin and myoglobin is:
- A. Consist of subunits designed to provide hydrogen bonds to and nonpolar interaction with other subunits.
While hemoglobin is a tetrameric protein consisting of two alpha and two beta subunits, each with quite different amino acid sequences and interactions, myoglobin is a monomeric protein with only one subunit, and its tertiary structure is stabilized by hydrophobic interactions. This means that myoglobin does not have subunits designed to provide hydrogen bonds to and nonpolar interaction with other subunits as it only has one subunit.