Which feature of the genetic code ensures that an amino acid can be coded by more than one codon?
Degeneracy of the genetic code means that multiple codons can specify the same amino acid. This follows from NCERT principle where the relation explains the outcome clearly for students in simple steps.
Ref: NCERT Biology Textbook for Class XI and XII (Botany section), Chapter: Morphology and Anatomy of Flowering Plants, Topic: Plant structure and tissue systems.