Studied by 3 people
why is there a need for specialised exchange surfaces for multicellular organisms
high metabolic activity, oxygen demands and carbon production
low surface area too volume ratio, larger distance to travel
why do exchange surfaces have increased SA
provide area needed for exchange, overcome limitations of small SA:V ratio
why do exchange surfaces have thin layers
shorter diffusion distances
why do exchange surfaces have good blood supply
maintain steep concentration gradient for diffusion
why do exchange surfaces have good blood supply
to maintain diffusion gradient
example of increased surface area in exchange surfaces
root hair cells in plants or villi in small intestine
example of thin layers in exchange surfaces
alveoli in lungs or villi in small intestine
example of good blood supply in exchange surfaces
alveoli of lungs, gills of fish or villi of small intestines
example of ventilation in exchange surfaces
alveoli or gills of a fish (flow of water carry dissolved gases)
Note 
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