exchanging substances

Question 1

what do organisms exchange substances with

Answer 1

their environment

Question 2

multicellular organisms need

Answer 2

exchange surfaces

Question 3

single called organisms have a

Answer 3

large surface area compared to their volume

Question 4

multicellular organisms have

Answer 4

a smaller surface area compared to their volume

Question 5

gas exchange occurs in the

Answer 5

lungs

Question 6

lungs contain millions of little air sacs called

Answer 6

alveoli

Question 7

how are alveoli specialised for diffusion of oxygen and carbon dioxide

Answer 7

large surface area
thin walls
good blood supply

Question 8

explain how alveoli work

Answer 8

they diffuse carbon dioxide in from the blood and oxygen into the blood

Question 9

where are villi located

Answer 9

small intestine

Question 10

villi provide a

Answer 10

big surface area

Question 11

why do villi need a big surface area

Answer 11

so digested food is absorbed more quickly into the blood

Question 12

what do villi have

Answer 12

single layer of surface cells
good blood supply