9. Why is blood needed by all the parts of a body?
Blood is needed by all parts of the body because it is an important part of the transport system of our body and performs the following these important functions:
(i) Transports oxygen from the lungs to all the body cells.
(ii) Carries carbon-dioxide, waste products back to the lungs so that it can be exhaled easily.
(iii) Blood fights against diseases and infections.