[问答题]
The diagram below is a simple outline of thpamk dw9) (9a;xt ww0iewsr f+imr9mdhz (hpa67rq 0ln:yq**2 nephron.
1.Name the structures labelled I, II, III and IV in the diagram.
2.State the functions of structures I and II from part (a).
3.Insects do not have kidneys or nephrons; they have the Malpighian tubule system instead. Compare and contrast the Malpighian tubule system with the nephron.