**Core Concept**
The genetic code is a set of rules used by living cells to translate information encoded within genetic material (DNA or RNA sequences) into proteins. One fundamental principle of the genetic code is that it is degenerate, meaning that more than one codon can code for the same amino acid.

**Why the Correct Answer is Right**
This phenomenon occurs due to the wobble hypothesis proposed by Francis Crick. During protein synthesis, the anticodon on the tRNA molecule recognizes the codon on the mRNA through a process called base pairing. However, the first base of the anticodon (5' end) is not strictly base-paired with the first base of the codon (3' end), allowing for some flexibility in the recognition process. This flexibility, known as wobble, allows multiple codons to be recognized by a single tRNA molecule, resulting in the same amino acid being incorporated into the growing polypeptide chain.

**Why Each Wrong Option is Incorrect**
**Option A:** This option is not relevant to the genetic code and its degeneracy.
**Option B:** This option is also not relevant to the genetic code and its degeneracy.

**Clinical Pearl / High-Yield Fact**
The genetic code is nearly universal across all forms of life, with only a few minor variations. This universality is a testament to the fundamental principles of molecular biology that underlie the process of protein synthesis.

**Correct Answer: D. Wobble hypothesis.**