A、They need very little energy. B、They’re found at all depths of the ocean. C、They live where there is no sunlight. D、They’re si

M: So, what is your biology project about?
W: It is about microorganisms that live by chemosynthesis.
M: Err...what’s chemosynthesis?
W: Well, it’s pretty complicated. You know how most life on Earth depends either directly or indirectly on sunlight?
M: You mean like plants get energy directly from sunlight, and animals eat plants, so they depend indirectly on sunlight?
W: Right. But down on the ocean floor, there is no sunlight. In some places though, there are hydrothermal vents, which are small cracks on the ocean floor. And these vents release heat and minerals from the inside of the Earth into the seawater. And all along the vents there are these unusual microorganisms. They are called archaean. And these archaean use chemical reactions to get their energy from the minerals. The minerals that are released by the vents. So their energy comes from chemical reactions, not sunlight.
M: So chemosynthesis is getting their energy from chemicals?
W: That’s right.
M: That makes archaean very different from other forms of life.
W: And their genetic makeup is very different, too. They are one sort of organisms just like bacteria are, but genetically they are as different from bacteria as we humans are.
M: Wah, that’s a really interesting project.