Introns in pre-mRNA:

A) code for specific protein domains.
B) are spliced out of the message.
C) move within the mRNA, giving rise to new exon combinations.
D) protect pre-mRNA from enzyme degradation.
E) code for important amino acid sequences.

Introns

Non-coding sections of an RNA transcript, or the DNA encoding it, that are spliced out before the RNA molecule is translated into a protein.

Pre-mRNA

RNA precursor to mRNA in eukaryotes; contains both introns and exons.

Exon Combinations

Variations in the assembly of exons during mRNA processing, resulting in different mRNA molecules from the same DNA sequence.