Single-celled organisms reproduce using binary fission. For example, bacteria are single-celled organisms. They reproduce using binary fission. Binary fission is the process of an organism splitting itself into two parts, with the parent's DNA in the new part.
RNA can do catalytic functions like enzymes. It carries genetic information and replicate itself. It also carries information about vesicles which carries it. RNA is less stable than DNA which confirms that genetic material is evolved from a less stable to highly stable form.