What is an exon?

a part of DNA that codes for a functional protein

a part of DNA that does not code for a functional protein

the beginning part of the DNA molecule

the end of part of the DNA molecule

The correct answer is: a part of DNA that codes for a functional protein.

Explanation:

Transcription is the process in which a DNA fragment is used to synthesize an mRNA strand that will later be used to code for a protein.

Not every part of the DNA codes for functional proteins, many fragments will be cut off through a process that occurs right after transcription and is called splicing.

During splicing, the introns (parts that do not code for functional proteins) in the DNA are chopped off, while the exons remain and are stuck together.

The beginning part of the DNA molecule is called a promoter and is where the RNA polymerase binds to in order to start transcription.

A part of the DNA that codes for a functional protein i believe