The RNA world hypothesis is best described as:

• A. A theory that proposes that early life was based on self-replicating RNA instead of DNA and protein
• B. A theory that life began with DNA and proteins already present
• C. A theory about the formation of the universe
• D. A theory that proposes RNA formed lipid membranes

Answer: (A)

The idea being tested is that early life used RNA as both genetic material and a catalyst, allowing self-replication before DNA and proteins existed. RNA’s ability to store information like DNA and to act as a catalyst like proteins (ribozymes) makes it plausible that it could support a self-sustaining, evolvable system in the origin of life. This dual functionality explains how heredity and metabolism might have arisen together in a single molecule, paving the way for the later transition to DNA for longer-term information storage and proteins for diverse catalytic skills. The other statements describe scenarios that don’t fit this sequence: starting with DNA and proteins, addressing cosmology, or suggesting RNA forms membranes, none of which capture the proposed RNA-first, self-replicating stage.