<span>a. spinal cord
Spinal Cord is the part of the nervous system responsible for connecting the brain to the body.
</span>The nervous system is divided into two groups. The Central Nervous System and the Peripheral Nervous System.
The Central Nervous System involves the Brain and the Spinal Cord. Its contains the integrative and control centers.
<span>The Peripheral Nervous System involves the cranial nerves and spinal nerves. It is composed of the communication lines between the Central Nervous System and the rest of the body.</span>
It consists of the alveolar wall, the capillary wall, and their basement membranes.
<u>Smoking</u> causes respiratory disorders such as bronchitis, pneumonia and lung cancer.
<u>Explanation:</u>
Respiratory disorders such as bronchitis, pneumonia and lung cancers are caused by smoking tobacco, air pollution and by infection. Smoking is the predominant cause of this respiratory order it also raises the level of air pollution which becomes hazardous to all the living organisms.
Infection in the lungs which is identified as pus in air sacs and found as inflamed lungs is usually life threatening. Severe shortness of breathe called the bronchitis is due to airborne chemicals.