In the given diagram showing the tertiary structure of a protein, the disulfide bond is shown by the letter:

1. A
2. B
3. C
4. D

In the tertiary structure of a globular protein, where do you expect to find the amino acids serine and alanine?
1. Serine would be in the interior, and alanine would be on the exterior of the globular protein.
2. Alanine would be in the interior, and serine would be on the exterior of the globular protein.
3. Both serine and alanine would be in the interior of the globular protein.
4. Both serine and alanine would be on the exterior of the globular protein.