AP BIOLOGY

Detailed explanation-1: -Tiny air sacs at the end of the bronchioles (tiny branches of air tubes in the lungs). The alveoli are where the lungs and the blood exchange oxygen and carbon dioxide during the process of breathing in and breathing out.

Detailed explanation-2: -It helps dissolve oxygen in the inhaled air for gas exchange.

Detailed explanation-3: -The fluid represents the outermost layer of the alveolar surface that is directly exposed to air and thus to the environment. Alveolar fluid prevents desiccation of the epithelial cells and also functions as a physical protection barrier against inhaled particles and irritants.

Detailed explanation-4: -The lungs and respiratory system allow us to breathe. They bring oxygen into our bodies (called inspiration, or inhalation) and send carbon dioxide out (called expiration, or exhalation). This exchange of oxygen and carbon dioxide is called respiration.

Detailed explanation-5: -The nose and trachea Breathing in through the nose warms and humidifies the air that is breathed in. Nose hairs help to trap any particles of dust. The warmed air enters the lungs through the windpipe, or trachea.