Complex sentence: The H/ACA box and C/D box snoRNAs are ncRNAs found in archaea and eukaryotes, RNase MRP is restricted to eukaryotes, both groups of ncRNA are involved in the maturation of rRNA.
Split into simpler sentences: The H/ACA box and C/D box snoRNAs are ncRNAs found in archaea and eukaryotes. Both groups of ncRNA are involved in the maturation of rRNA.