If the nucleotide sequence of a section of DNA that codes for a protein is changed, which of the following has occurred?

Transcription is the process by which the information in a DNA sequence is copied into messenger RNA (mRNA). While transcription is crucial for gene expression, it does not involve any changes to the DNA sequence itself. Therefore, transcription cannot be the correct answer, as it does not imply any alteration to the nucleotide sequence.

A new adaptation refers to a change in a species that enhances its survival and reproduction in a specific environment. While mutations can lead to adaptations over time, the mere change in a nucleotide sequence does not directly equate to the establishment of an adaptation. Adaptations result from a series of changes that may or may not stem from a single mutation.

Natural selection is the process by which organisms better adapted to their environment tend to survive and produce more offspring. While natural selection can act on mutations, the occurrence of a nucleotide sequence change itself does not imply natural selection has taken place; it simply indicates a mutation has occurred.