The answer is D 
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Answer:
The respiratory system is a biological system consisting of specific organs and structures used for gas exchange in animals and plants. The anatomy and physiology that make this happen varies greatly, depending on the size of the organism, the environment in which it lives and its evolutionary history. In land animals the respiratory surface is internalized as linings of the lungs. Gas exchange in the lungs occurs in millions of small air sacs called alveoli in mammals and reptiles, but atria in birds. These microscopic air sacs have a very rich blood supply, thus bringing the air into close contact with the blood. These air sacs communicate with the external environment via a system of airways, or hollow tubes, of which the largest is the trachea, which branches in the middle of the chest into the two main bronchi. These enter the lungs where they branch into progressively narrower secondary and tertiary bronchi that branch into numerous smaller tubes, the bronchioles. In birds the bronchioles are termed parabronchi. It is the bronchioles, or parabronchi that generally open into the microscopic alveoli in mammals and atria in birds. Air has to be pumped from the environment into the alveoli or atria by the process of breathing which involves the muscles of respiration.
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Pancreatitis is an inflammation of the pancreas that may be caused by years of heavy consumption of alcohol of gall stones. The pancreas plays major important roles such as secreting digestive juices into the small intestines, which help to digest fats, proteins, and the carbohydrates in food. It also release hormones insulin and glucagon that regulate the blood sugar. Pancreatitis is characterized by a pancreas being inflamed, therefore when this happens the body's normal complex coordination is disrupted and the enzymes in the pancreas are prematurely activated before they exit the organ, which results in these enzymes digesting the pancreatic tissue.
        
             
        
        
        
Answer:
Dietary fiber refers to a group of substances in plant foods which cannot be completely broken down by human digestive enzymes. This includes waxes, lignin and  polysaccharides  such as cellulose and pectin. Originally it was thought that dietary fiber was completely indigestible and did not provide any energy.
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