Which of the following best describes the function of introns and exons in eukaryotic cells?

The assertion that exons are coding regions and introns are non-coding is accurate in the context of eukaryotic cells. Exons are sequences within a gene that are retained in the final messenger RNA (mRNA) after the transcription process. These sequences contain the necessary information to produce proteins, making them crucial for the expression of genes.

On the other hand, introns are segments of a gene that are transcribed into precursor mRNA but are subsequently removed during RNA splicing before translation occurs. These non-coding regions do not contribute to the final protein product. Thus, the distinction between the two is essential for understanding gene expression and the processing of mRNA in eukaryotic cells, emphasizing the role that exons play in coding for proteins while introns serve primarily as spacer regions that are excised from the mRNA.