Question

through what does the air enter tracheal system in insects? what type of respiratory surface should be for rapid and efficient gaseous exchange

Answer 1

Insects breathe through tiny pores called spiracles present along side of their body and these pores are attached to tracheal system inside the body.
Tracheal system consists of a network of air tubes called tracheae that open outside through spiracles. Oxygen rich air rushes through pores into the tracheal tubes, diffuses into the body tissue, and reaches every cell of the body. Similarly, carbon dioxide from the cells goes into the tracheal tubes and moves out through pores.

Properties of respiratory surface:

• Respiratory surfaces should have large surface area to ensure maximum contact with air or water.
• Respiratory surfaces should always be moist.
• Respiratory surfaces should extremely thin.
• Inside they should be in contact with capillary that allows gaseous exchange between blood and surrounding air or water.