living organisms need to respire. respiration requires oxygen (O2) and produces carbon dioxide (CO2) as a waste products. to maintain suitable internal (homeostatic) conditions, these gases must be efficiently exchanged. animals have evolved a number of gaseous exchange systems to meet their needs.
insect:- use holes and pipes in their skin
air enters the spiracles and fills the trachea (a network of tubes)
there is a concentration gradient (high O2in trachea, low in cells) so O2 diffuses into the body (CO2 is low in trachea and high in cells so it diffuses out)
fish:- larger organisms must have a distribution system to get O2 (& nutrients) to…