Let me explain:

* mRNA (messenger RNA) is a type of RNA that carries genetic information from DNA to the ribosomes, where proteins are made.

* Codons are groups of three consecutive nucleotides (adenine, guanine, cytosine, or uracil) within mRNA.

* Each codon specifies a particular amino acid or signals the start or stop of protein synthesis.

There are 64 possible codons, but only 20 amino acids are commonly found in proteins. This means that some amino acids are coded for by more than one codon.

Here's an example:

* The codon AUG codes for the amino acid methionine and also serves as the start codon for protein synthesis.

* The codons UAA, UAG, and UGA are stop codons, signaling the end of protein synthesis.

Understanding codons is essential for understanding how genetic information is translated into proteins, which are the building blocks of life.