the answer is B by the number of valence electrons.
In humans, the medulla region of the brain is mainly responsible for the regulation process of respiration. It is also called the respiratory rhythm centre. The chemosensitive area located near the respiratory centre sends signals across nerve impulses to alter the rate of expiration to eliminate compounds.
The Abdominopelvic cavity Hope this helps :)
A functional disorder is a medical condition that impairs normal functioning of bodily processes that remains largely undetected under examination, dissection or even under a microscope. At the exterior, there is no appearance of abnormality. This stands in contrast to a structural disorder (in which some part of the body can be seen to be abnormal) or a psychosomatic disorder (in which symptoms are caused by psychological or psychiatric illness). Definitions vary somewhat between fields of medicine.
Generally, the mechanism that causes a functional disorder is unknown, poorly understood, or occasionally unimportant for treatment purposes. The brain or nerves are often believed to be involved. It is common that a person with one functional disorder will have others.
