(a) State one function of each of the following structures:
(i) Arteries
(ii) Capillaries
(iii) Veins
(iv) Xylem
(v) Phloem

(b) Describe the changes that take place in the composition of human blood as it passes through the:
(i) Lungs
(ii) Liver
(iii) Kidneys
(iv) Small intestine

(c) List the cellular components of blood.