Assertion: The first cells used RNA as their hereditary molecule.
Reason: DNA evolved from RNA.
Answer & explanation
Correct answer: option 2
The RNA world is proposed as the first stage in the evolution of life in which RNA catalysed all molecules necessary for survival and replication. If the first cells used RNA as their hereditary molecule, DNA evolved from an RNA template. DNA probably did not evolve as a hereditary molecule until RNA based life became enclosed in a membrane. Once cells evolved, DNA probably replaced RNA as the genetic material for most organisms.