Answer:
Exons.
Explanation:
In mRNA maturation and processing, a complex called a splicesome essentially "cuts out", if you will, non-coding parts of the DNA sequence to be translated. The parts that are cut out are called "introns", and the parts that are left over that code for a protein sequence, are called "exons". Careful with the terminology. It seems counterintuitive that exons are the ones that stay (exon = exit? NO.) and introns (in, as in, stays in? NO.) are the ones that are cut out of the mature mRNA. Perhaps you can remember that the terms seem to be the opposite, that's how I remember it. Alright, good luck with all of this.
