Biology Revision for "O" level examinations

ANSWERS SELECTED ARE NOT NECESSARY CORRECT

Respiration Adaptation of the respiratory tract -nasal cavity, trachea, and bronchi are line with cilia, which traps dusts and microbes from entering the lungs. Goblet cells along the tract produce mucus that also traps dusts and microbes. -air entering tract is moistened - Alveoli, found at the end of bronchioles, are one cell thick to allow quick diffusion of gases -alveoli are covered with a dense network of capillaries -each lungs have millions of alveoli to increase surface area - if too much dust enters the tract, a sneeze occurs, to force the dust particles out of respiratory tract   Movement of air Nose /mouth --> trachea--> bronhus (two bronchi present)--> bronchole --> alveolus (air sac) Breathing Inhalation -intercostal muslces contract causing the rib cage to move upwards and outwards -the diaphragm muscles contract causing the diaphragm to flatten -this causes the volume in the lungs to increase, while the pressure decre