Answer:
A
Explanation:
In such an isolated ecosystem, there is usually an autotroph species that coverts the abiotic elements in the environment to biotic elements. In a hydrothermal vent, it is likely that there are some chemoautotrophic bacteria that covert the sulfur and other chemicals in the water into organic molecules. This energy is then transferred up the food web in the closed ecosystem. In such an ecosystem, even the waste product of one life form may be utilized by another species.
