Formative Practice 8.1 (Form 4 Biology Textbook Exercise and Answer)


Question 1:
State the adaptations of the human respiratory structure.

Answer:
• The large number of alveoli provides a large surface area for gaseous diffusion.

• The inner lining of alveoli is always moist and enables respiratory gases dissolve in it

• The alveoli are covered with a dense network of blood capillary that speeds up the diffusion of respiratory gases.

• The alveolus wall is only one-cell thick, which eases gas diffusion


Question 2:
Explain how the frog skin is adapted for efficient exchange of gases.

Answer:
A frog’s skin is very thin, constantly moist and densely supplied with a network of blood capillaries.


Question 3:
State the characteristics of tracheoles that help with gaseous exchange in insects.

Answer:
• The large number of tracheoles provides a large surface area for gaseous exchange.

• Each body cell in an insect is supplied with a tracheole.

• The walls of tracheoles are thin and constantly moist.

• The ends of tracheoles have permeable walls and contain fluids that enable respiratory gases to dissolve and diffuse in and out of the respiratory surfaces.


Question 4:
Predict what will happen to a fish if its gills are torn after being caught in a net.

Answer:
Damaged gills reduce the total surface area available for an efficient gaseous exchange. Thus the fish may die due to a lack of oxygen.

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