Complex sentence: Circular RNA (or circRNA) is a type of RNA which, unlike the best known linear RNA, forms a covalently closed continuous loop, i.e., in circular RNA the 3'and 5' ends normally present in an RNA molecule have been joined together.
Split into simpler sentences: Circular RNA (or circRNA), unlike linear RNA, forms a covalently closed continuous loop. In circular RNA the 3'and 5' ends normally present in an RNA molecule have been joined together.