Surface area : Volume ration + Lungs

How quickly an organism can get nutrients by diffusion or absorption

The amount of energy expended by the organism in a time period , usually daily

Determines how much nutrients an organism needs

How much oxygen and nutrients an organism needs to take in daily to respire enough to maintain that metabolic rate

Movement of air into and out lungs

: Chemical reaction to release energy

Diffusion of oxygen from the air in the alveoli into the blood and carbon dioxide from the blood into the air out of the alveoli

One muscle relaxed whilst another is contracted a tthe same time

External intercostal muscles contract and ribcage moves out Internal intercostal muscles relax Diaphragm goes down to create more volume in the lungs Pressure decreases due to this Air goes into the lungs as the pressure gradient is high to low in the lungs

External intercostal muscles relax Internal intercostal muscles contract and ribcage moves in Diapragm goes up to create less volume in the lungs Pressure increases due to this Air goes out the lungs as the pressure gradient is high to low in the air

Liquid surfactant

Oxygen in the alveoli sacs is highly concentrated so oxygen diffuses into the blood as it is low concentrated in there and they are right next to eachother

Thin permable walls