xerophytes

Habitat= the place in which organisms lives

adapations= A postitive characteristic of an organism that has been favoured by natural selection 

Water molecule= A measure of the tendency of water molecules to diffuse from one place to another 

Stomata= The tiny opening/ pore, found at the underside of the plants leaf and used for gas exchange 

Transpiration= the evaportation of water from the aerial parts of plants, esspecially leaves but also stems, flowers and roots

Gaurd cells= occur in pairs and are shaped so that a pore or stomata exists between them.

All aerobic organisms rquire a constant supply of oxygen for respiration and the realease of ATP from glucose

the gas exchange system in humans is a 2 way process as co2 needs to be removed as it can be harmful 

the volume of oxygen that has to be absorbed is large in mammals because;

1 they are large organisms with a large volume of living cells

2 they maintain high body temperature and therefore have high metabolic and respiratory rates

all mammals have lungs to ensure efficient gas exhange between the air and there blood