Final answer:
The correct answer is 'd. exons,' which represent the segments of DNA that code for protein production in eukaryotic organisms.
Step-by-step explanation:
In eukaryotic organisms, the segments of DNA that are involved in coding for the production of proteins are called exons. Exons are the regions of a gene that, after processing, relate directly to the corresponding protein. Unlike exons, which contain the actual genetic instructions, introns are non-coding segments of a gene that are ultimately removed from the pre-mRNA sequence during RNA splicing. Following the removal of introns, the remaining exons are spliced together to form a continuous sequence that determines the amino acid sequence in a protein.
Therefore, when considering the choices presented, the correct answer is 'd. exons', as they correspond to the protein-coding regions of a gene. It is essential for proper protein synthesis that these exons are joined correctly; if this processing is carried out incorrectly, alterations in the resulting protein can lead to dysfunctional proteins, which may affect cellular function and health.