Question

The role of the respiratory system is to breathe in oxygen and breathe out carbon dioxide. This is known as respiration. The cells of the body use oxygen to perform functions that keep us alive. The waste product created by the cells once they have performed these functions is carbon dioxide. The respiratory system is made up of the nose, mouth, throat, trachea (windpipe) and lungs. The diaphragm is the main breathing muscle of the body. The accessory breathing muscles assist the diaphragm and are made up of muscles surrounding the ribs, abdominal muscles and muscles in the neck and shoulders. When the diaphragm and accessory muscles contract, your chest expands and pulls air into the lungs; this is inhaling. As your muscles relax, the space inside your chest gets smaller and under more pressure and the air is pushed out of the lungs; this is exhaling - similar to letting air out of a balloon. The cells of the body use oxygen to produce energy. Oxygen is carried by the hemoglobin on the red blood cells. The blood vessels in the lungs bring oxygenated blood to the heart. The heart then pumped it out to the cells of the body. The waste product of this process is carbon dioxide. The hemoglobin then returns the carbon dioxide back to the lungs where it is exhaled. The amount of oxygen needed by the body varies. It will depend on a person's level of activity, age, weight, and overall health. Individuals who are ill or injured may require more oxygen to help their bodies function and heal. craighospital.org The purpose of the text above is ….
a. .to tell how breathing muscle of the body works
b. .to explain the process of breathing in human body
c. to explain the parts of respiratory system
d. to tell how cells work in our body system.
e. to explain the role of respiratory system in all living things​

Answer 1

b. to explain the process of breathing in human body.