1, discuss the classification of respiratory system biased on number and arrangement of functional spiracle?

The respiratory system of insects can be classified based on the number and arrangement of functional spiracles. Spiracles are small openings on the body of insects that allow for the exchange of gases, such as oxygen and carbon dioxide, with the environment.

1. Holopneustic: Insects with a holopneustic respiratory system have a single pair of spiracles located at the posterior end of the body. This type of respiratory system is found in primitive insects, such as silverfish and mayflies.

2. Amphipneustic: Insects with an amphipneustic respiratory system have multiple pairs of spiracles located along the body. This type of respiratory system is found in more advanced insects, such as beetles and grasshoppers.

3. Metapneustic: Insects with a metapneustic respiratory system have a combination of holopneustic and amphipneustic characteristics. They have a single pair of spiracles at the posterior end of the body, as well as additional spiracles located along the body. This type of respiratory system is found in insects like dragonflies and damselflies.

Overall, the classification of the respiratory system based on the number and arrangement of functional spiracles reflects the evolutionary adaptations of insects to efficiently exchange gases with their environment.