I believe the correct answer is Digestive System
We usually eat food in order to be able to obtain energy and nutrients necessary for survival. But the food must be prepared and broken down into micro molecules for it to be absorbed fully into the bloodstream and supplied to the body. This task is given to the digestive system.
This is a system which functions to clean blood by taking out carbon dioxide and adding oxygen into the blood. Oxygen is carried in specific blood cells called red blood cells. The oxygen is bound to a chemical called hemoglobin inside the red blood cells that makes your blood appear red.
This is the system which prepares food for absorption. It is hollow and starts from your mouth where the food is broken down into smaller particles and a nutrient called starch is absorbed with the aid of saliva. The food then goes down via the esophagus up to the duodenum and to the stomach where proteins are absorbed and the food is converted into a semi-solid form called chyme. The chyme then enters the small intestines where carbohydrates, lipids and fats are absorbed. Digestion ends here and absorption starts in the same small intestines. The small intestines are adapted to absorb the food via small microvilli on its wall into the bloodstream. The chyme now has been absorbed of all its nutrients and proceeds to the large intestines where water and ions is absorbed leaving only the waste products. They then are taken to the rectum in preparation to going to the toilet where you pass them as feces through the anus.
This is responsible for communication of body parts. It has specific cells called neurons that perform its functions. It is divided into the central nervous system that includes the brain and the spinal cord and the peripheral nervous system that contains neurons in all the other body parts except the brain and the spinal cord.
It is the system that removes waste from the body. It includes the skin which removes waste through sweating, the kidneys which are bean shaped organs in the abdomen that purify blood and remove the waste as urine. Part of the digestive system also performs excretory functions and that is the anus and the rectum.
Level: High School
Subject: Biology
Topic Digestion
