Final answer:
Small nuclear ribonucleoproteins (snRNPs) are a complex of RNA and protein involved in splicing to remove introns from mRNA, predominantly found in eukaryotes.
Step-by-step explanation:
Small nuclear ribonucleoproteins (snRNPs) are indeed a complex of RNA and protein and are involved in the removal of introns from mRNA during the splicing process. snRNPs combine with other proteins to form spliceosomes, which recognize introns in pre-mRNA and catalyze their precise removal, resulting in an mRNA that consists only of exons, the coding regions for proteins. Although snRNPs are prominent in eukaryotes due to the presence of introns in their pre-mRNA, the question's statement that snRNPs are only found in eukaryotes is not entirely accurate, considering that self-splicing introns such as Group I or Group II can also be found in lower eukaryotes and prokaryotes, but their splicing mechanisms do not rely on snRNPs.