Concept:The respiratory organ of a cockroach is a system of air tubes called tracheae.
Explanation:Air enters the cockroach through small openings known as spiracles on the sides of its body.
These spiracles lead into a network of branching tubes called tracheae.
The tracheae extend throughout the body and divide into tiny tubes that reach the tissues.
Oxygen passes directly from these tubes into the cells, and carbon dioxide moves out through the same system.
The cockroach does not use blood to carry respiratory gases because the tracheal tubes deliver oxygen directly to the tissues.
Among the options, air sacs belong to birds, lung books are found in spiders and scorpions, and lungs are organs of mammals.
Therefore, the correct respiratory organ of a cockroach is the trachea.
Answer:B. trachea