surface area to volume ratio

Question 1

how does an organisms size relate to their surface area to volume ratio ?

Answer 1

larger organism: lower SA:V

Question 2

how does SA : V affect transport of molecules ?

Answer 2

lower SA : V = further distance molecules need to travel = insufficient diffusion

Question 3

why do larger organisms require mass transport and specialised gas exchange surfaces ?

Answer 3

• smaller SA : V
  harder to enter cell - mass transport and exchange surfaces facilitate exchange of substances