Which of the following organisms at black smokers uses sulfur as an energy source?

Red tube worms are organisms that thrive in the extreme environments found near black smokers, also known as hydrothermal vents. These organisms utilize sulfur as an energy source through a process called chemosynthesis. In this process, specialized bacteria within their bodies convert the hydrogen sulfide that is abundant in the water around the vents into energy. The tube worms rely on these chemosynthetic bacteria to produce organic compounds that they need for growth and sustenance.

The unique environment of black smokers, characterized by high temperatures and pressure, along with the availability of sulfur and other minerals, makes it possible for these tube worms to flourish, despite the absence of sunlight. This habitat is in stark contrast to photosynthetic organisms, which depend on sunlight for energy. The other choices, such as white crabs, photosynthetic algae, and coral polyps, either do not solely depend on sulfur or are not specifically adapted to the extreme conditions of hydrothermal vent ecosystems. Therefore, red tube worms represent the organisms that specifically use sulfur as an energy source in that unique ecological context.