Question

Why is DNA and not RNA, the genetic material in majority of organisms?

Answer 1

With the exception of certain viruses, DNA rather than RNA carries the hereditary genetic code in all biological life on Earth.

The following characters of DNA render to that fact that it is the genetic material in the majority of organisms:

DNA is both more resilient and more easily repaired than RNA. As a result, DNA serves as a more stable carrier of the genetic information that is essential to survival and reproduction.

DNA's info is better protected than RNA.

Double strands allow double-checking.