Final answer:
The abyssal zone of the ocean, characterized by low temperatures, no light, and high pressures, is the zone being referred to.
Step-by-step explanation:
The ocean zone with a temperature of about 4°C, no light, and high pressures is the abyssal zone.
The abyssal zone is the deepest part of the ocean, at depths of 4000 meters or greater. It is very cold, has very high pressure, and low nutrient content. The abyssal zone does not have light, so photosynthetic organisms cannot survive there, but it does have a variety of invertebrates and fishes.
Chemosynthetic bacteria use the hydrogen sulfide and other minerals emitted from deep hydrothermal vents as an energy source and serve as the base of the food chain found in the abyssal zone.