Which of the following correctly describes the primary and tertiary structures of a protein?
A. The primary structure is the amino acid chain; the tertiary
structure is the protein's shape.
B. The primary structure is the amino acid chain; the tertiary
structure is the mRNA sequence.
C. The primary structure is the mRNA sequence; the tertiary structure
is the amino acid chain.
D. The primary structure is the protein's shape; the tertiary structure
is the amino acid chain.