RRB RPF RPSF SI and CONS Model Papers 7 with solutions

(1) Insects, and some other invertebrates, exchange oxygen and carbon dioxide between their tissues and the air by a system of air-filled tubes called tracheae. It is a complex network of tubes (called a tracheal system) that delivers oxygen-containing air to every cell of the body. Tracheae open to the outside through small holes called spiracles.