Which zone is known for having no sunlight and supporting no photosynthesis?

• A. Surface zone
• B. Deep zone
• C. Mesopelagic zone
• D. Epipelagic zone

Answer: (B)

Light is the energy source for photosynthesis, so zones without light cannot support it. The deep zone has no sunlight at any depth year-round, making photosynthesis impossible there. In contrast, the surface and epipelagic zones are lit and support photosynthesis, while the mesopelagic receives only faint, dim light that isn’t enough for most photosynthesis. So, the deep zone is the region characterized by perpetual darkness and the absence of photosynthetic production.