Which one of the following is one of the paths followed by air/O₂ during respiration in an adult male Periplaneta americana as it enters the animal body?

Options

(a) Hypopharynx, mouth, pharynx, trachea, tissues
(b) Spiracle in metathorax, trachea, tracheoles, oxygen diffuses into cells
(c) Mouth, bronchial tube, trachea, oxygen enters cells
(d) Spiracles in prothorax, tracheoles, trachea, oxygen diffuses into cells

Correct Answer:

Spiracle in metathorax, trachea, tracheoles, oxygen diffuses into cells

Explanation:

The no. of spiracles in cockroach is 10-pairs (2-pairs in thoracic and 8-pairs in abdominal region). The thoracic pairs of spiracles are present on pleuron between prothorax – mesothorax and metathorax. Each spiracle open into a chamber called atrium. After atrium the tracheal tube ramifies into fine branches of tracheae, and then tracheoles.