(a)[2]
Describe what the term excretion means.
(b)[1]
State the name of the substance released by the lungs in excretion.
(c)[3]
State the names of the parts marked P, Q and R in Fig. 4.1.
(d)[6]
Describe and explain how the composition of the fluids in structures X, Y and Z in Fig. 4.2 differs.
(e)[2]
Describe two ways amino acids are handled in the liver.