Natural selection mostly selects against change. Without selection the cockroach would have mutated. Viruses are not an enigma, another parasitic genetic eleme

Natural selection mostly selects against change. Without selection the cockroach would have mutated. Viruses are not an enigma, another parasitic genetic element are Inteins - https://en.wikipedia.org/wiki/Intein https://en.wikipedia.org/wiki/Intein.