1. It is part of tracheal respiratory system in insects.
2. Fine intercellular tubes present deep into cells.
3. End blindly in cells.
4. Filled with watery fluid at blind end.
1. It is part of respiratory system (lungs) in man.
2. These are not intercellular but they present in lungs.
3. Branch further and end ultimately in alveolar sacs.
4. Not filled with watery fluid.