In the genetic code, a codon consists of three consecutive:

• A. amino acids
• B. nucleotides
• C. genes
• D. chromosomes

Answer: (B)

Verified step by step guidance

1. Understand the basic structure of the genetic code: DNA and RNA sequences are made up of nucleotides, which are the building blocks of these molecules.
2. Recall that a codon is a sequence of three nucleotides in mRNA that corresponds to a specific amino acid or a stop signal during protein synthesis.
3. Recognize that amino acids are the products specified by codons, not the components of codons themselves.
4. Note that genes are segments of DNA that contain instructions for making proteins, and chromosomes are structures that organize DNA, but neither are the direct components of a codon.
5. Therefore, conclude that a codon consists of three consecutive nucleotides.