Final answer:
A chemoautotroph is an organism capable of synthesizing its own food using energy from inorganic molecules. They are found in rare ecosystems like hydrothermal vents and play a primary role in the food web by supplying energy to other organisms.
Step-by-step explanation:
A chemoautotroph is an organism that is capable of synthesizing its own food using energy from inorganic molecules. An example of a chemoautotroph is bacteria found in rare ecosystems like hydrothermal vents at the bottom of the ocean, which use hydrogen sulfide as a source of energy to produce complex organic molecules, such as glucose. Chemoautotrophs play a crucial role in the food web as they are the primary producers in these unique ecosystems, supplying energy to the rest of the organisms.