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.

carbon is found in all living things. carbon atoms move constantly through

living organisms, the oceans, the atmosphere, and the earth’s crust in what is

known as the carbon cycle. the directions taken by carbon atoms through this

cycle are very complicated and can take millions of years to make a full circle.

all animals, from humans to the dinosaurs are part of the carbon cycle. when

animals eat food, they get carbon in the form of carbohydrates and proteins.

in animals, oxygen combines with food in the cells to produce energy for daily

activity and then gives off carbon. the carbon combines with oxygen to form

carbon dioxide (co2) and is released back into the atmosphere as a waste

product when animals breathe and exhale.

from 145-65 million years ago, earth was much

hotter than today and covered with dense,

tropical swamp forests. the trees and other

plants were immense and

provided an endless supply of

food for the giant animals that

roamed the land. somewhere in

the air above one of these

forests, a lone carbon atom has joined

up with two oxygen atoms to form a molecule of co2.

the co2 molecule was sucked into the tiny holes (stomata) on the leaf of a

fern plant and joined with sunlight, chlorophyll and water to make food and

energy in the plant’s cells through photosynthesis. the oxygen (o2) from the

co2 molecule was sent back into the atmosphere; the carbon atom (c) was

detached and used to make a molecule of sugar.

if that carbon atom had been eaten instead, a totally

different situation would have developed. let’s say

that a giant plant-eating dinosaur (herbivore) ate the

fern for breakfast, and swallowed the carbon in the

fern in the form of carbohydrates and proteins. in

the process of respiration, oxygen combined with

the carbohydrates and proteins in the dinosaur’s cells

to provide energy for its daily activity.  

no simpler subs form complex ones. synthesise = make