The prokaryotic ribosomes are $80 \mathrm{~S}$, where $S$ stands for sedimentation coefficient
These are composed of ribonucleic acid and proteins
These are found only in eukaryotic cells
These are self-splicing introns of some RNAs
Solution
Ribosomes are large, non-membranous, RNA-protein complexes which are necessary for protein synthesis. In prokaryotes, $70 \mathrm{~S}$ type of ribosomes are found while $80 \mathrm{~S}$ type of ribosomes are found in eukaryotes.