Primary molecule : Peptide bond :: Tertiary molecule : ______

Explanation

To solve the analogy presented in the question, we need to identify the relationship between the primary molecule and the peptide bond, and then apply that understanding to find the corresponding bond for the tertiary molecule.

### Step-by-Step Solution:

1. **Understand the Primary Structure**: The primary structure of a protein is defined as the linear sequence of amino acids. These amino acids are linked together by peptide bonds. Therefore, the primary molecule is associated with peptide bonds.

2. **Identify the Tertiary Structure**: The tertiary structure of a protein refers to its three-dimensional shape, which is more complex than the primary structure. This structure is stabilized by various types of bonds and interactions.

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