Final answer:
The presence of water on ancient Mars suggests it may have been habitable but does not prove that life existed. Future missions focusing on sample return will be critical in the search for past Martian life.
Step-by-step explanation:
The existence of water in the past on Mars does not prove that there was life. Discoveries on Mars, such as the presence of water ice, water vapor in the atmosphere, organic compounds, and evidence of ancient wet environments from rovers such as Curiosity, support the notion that Mars may have once been habitable. Yet, this habitability does not equate to the definitive existence of life. Future missions aim to return samples to Earth for detailed analysis to better understand if life ever existed on Mars.