Final Answer:
The molecule that led scientists to explore the role of RNA in the origin of life is 3) RNA.
Step-by-step explanation:
The exploration of RNA's role in the origin of life gained prominence due to the molecule's unique properties. Unlike DNA, RNA is capable of both storing genetic information and catalyzing chemical reactions, particularly in the form of ribozymes. This dual functionality suggests that RNA may have played a crucial role in early biochemical processes, possibly preceding the emergence of DNA and proteins. The RNA world hypothesis proposes that, in the primordial soup, self-replicating RNA molecules served as precursors to life, with RNA acting as both a repository of genetic information and a catalyst for essential reactions. While DNA and proteins are integral to life, it was the distinctive properties of RNA that prompted scientists to investigate its potential central role in life's origin.
Option 3) RNA is the answer.