Gills enhance diffusion between aquatic creatures' blood and the surrounding water. They have a large surface area to increase the area available for gas exchange and a lot of capillaries to increase the bloodflow through the gills.
Answer;
Central Nervous system
Explanation;
-The body is in a continual state of hunger, which is intermittently relieved by eating.
-The central nervous system (CNS) controls most functions of the body and mind. It consists of two parts: the brain and the spinal cord. The brain is the center of our thoughts, the interpreter of our external environment, and the origin of control over body movement.
-The part of the brain which controls hunger is the Hypothalamus. It is the Main regulatory organ for apetite. It is a section of the brain which is responsible for hormone production. The hormones produced by this area of the brain governs body temperature, thirst, hunger, sleep, mood.
In the nature-nurture issue, nature refers to an organism's environmental inheritance, nurture to its issues.
Hope thissss helped!! :D have a great day.