1. what is a deep - sea environment?\n2. how deep is the ocean considered to be a deep - sea…

Brief Explanations:

1. A deep - sea environment is a part of the ocean that is far below the surface, characterized by extreme conditions.
2. Generally, depths below 200 meters are considered deep - sea environments, though this can vary.
3. One characteristic is high pressure due to the weight of the overlying water.
4. Bioluminescence is the production and emission of light by a living organism, often used for communication, predation, or defense in the deep - sea.
5. Organisms around hydrothermal vents use chemical energy from the compounds in the vent fluids, like hydrogen sulfide, through chemosynthesis.
6. A hydrothermal vent is a fissure in the ocean floor from which geothermally heated water emerges.
7. An example of a deep - sea organism is the anglerfish.
8. Tube worms rely on symbiotic bacteria that perform chemosynthesis using the chemicals from hydrothermal vents for nutrition.
9. It is difficult to study deep - sea ecosystems due to extreme pressure, lack of light, and the vast distances and inaccessibility.
10. Hydrothermal vents were first discovered in 1977 during the Alvin expedition.

Answer:

1. A part of the ocean far below the surface with extreme conditions.
2. Depths below 200 meters (can vary).
3. High pressure.
4. Light production by living organisms.
5. Chemical energy through chemosynthesis.
6. A fissure in the ocean floor with geothermally heated water.
7. Anglerfish.
8. Symbiotic bacteria performing chemosynthesis.
9. Extreme pressure, lack of light, inaccessibility.