Given below is a schematic representation of the circulatory system in man. Study the same and answer the questions that follow:
(i) Label the parts 1 to 4 indicated in the diagram.
(ii) Give one difference between the parts 1 and 2 based on:
(a) their structure
(b) the nature of blood flowing through them.
(iii) What is the specific name of the type of blood circulation that takes place between the heart and the lungs ?
(iv) Name the valve found at the beginning of the part labeled 3.
