Respiration in insects is called direct becausea. The tissues exchange O2?/ CO2directly with the air in the tubesb. The tissues exchange O2?/ CO2directly with coelomic fluidc. The tissues exchange O2?/ CO2directly with the air outside through body surfaced. Tracheal tubes exchange O2?/ CO2?directly with the haemocoel which then exchange with tissues
(d). Direct respiration which refers to he exchange of gases without any special respiratory organ and blood. In insects, the tracheal tubes exchange O2 and CO2 directly with the haemocoel which then exchange them with tissues.