Given alongside is the figure of certain organs and associated parts in the human body. Study the same and answer the questions that follow :
(a) Name all the organ-systems shown completely or even partially.
(b) Name the parts numbered 1 to 5.
(c) Name the structural and functional unit of the part marked '1'.
(d) Name the two main organic constituents of the fluid that flows down the part labelled '3'.
(e) Name the two major steps involved in the formation of the fluid that passes down the part labelled '3'.