Known as the twilight zone, the mesopelagic zone meets the photic zone above and becomes very dark as depth increases. temperature decrease; pressure increases. because nutrients are limited here, some animals rise to the photic zone at night for food. many animals in this subzone can eat animals larger than themselves because they are equipped with large sharp teeth with expandable jaws and stomachs. another key physical feature of animals living in this zone is which has a variety of purposes, including predator deterrence, communication, and lures for prey. a) symbiosis b) transparency c) bioluminescence d) oversized scales

C) bioluminescence

The middle layer of the world's ocean receives very little sunlight. This oceanic layer is called as twilight zone or diphotic zone or mesopelagic zone. This zone appears blue to black in color. The animals that live in this zone are adapted to survive in darkness, high pressure and cold water conditions.

The animals in this zone exhibit large eyes, which helps them to see in dark waters. Most animals are small, thin and dark which helps them to camouflage the predators in darkness. Some animals also possess large teeth and jaws. Many of these animals show bio luminescence, which means they can produce their own light. They have special organs which helps them to produce light by chemical reactions. Animals use light to find food and mates, they camouflage and distract the predators by light.

absorption lines are where light has been absorbed by the atom thus you see a dip in the spectrum whereas.

emission spectra have spikes in the spectra due to atoms releasing photons at those wavelengths.

explanation: