Final answer:
Organisms that can obtain energy from alternative sources or reduce their dependence on organic molecules would have a survival advantage as the supply of organic molecules decreases.
Step-by-step explanation:
As the supply of organic molecules decreases, organisms that have a survival advantage are those that can obtain energy from alternative sources or reduce their dependence on organic molecules. One possible advantage is the ability to capture free energy from inorganic molecules or sunlight through processes like chemosynthesis or photosynthesis. These organisms, known as autotrophs, can generate organic molecules and replenish nutrients in their environment. This allows them to survive even when the supply of organic molecules is limited.