Question

what is a mutation?
○ a change in the nucleotide sequence of dna
○ a change in the structure of a protein
○ a cause of a disease
○ a change in the function of a protein

Explanation:

A mutation is defined as a change in the nucleotide sequence of DNA. Changes in protein structure or function (options 2 and 4) can be a consequence of a mutation, not the definition. While mutations can cause diseases (option 3), this is also not the core definition of what a mutation is. The key and most fundamental description is related to the DNA nucleotide sequence change.

Answer:

a change in the nucleotide sequence of DNA