Write two important functions of Amniotic fluid.

The diagram given alongside is the longitudinal section of a human kidney. Study the diagram and answer the questions that follow.

(i) Label the parts numbered 1 and 3.

(ii) Name the fluid that passes down from the part numbered as 4. Also write its main nitrogenous constituent.

(iii) Why does part 2 show a striped appearance?

Distinguish between Biodegradable and Non-biodegradable waste

What is placenta? Write its one important role.