Question
A liquid X of colour Y circulates in the human body only in one direction : from body tissues to the heart.Among other things, liquid X contains germs from cells and dead cells. The liquid X is cleaned of germs and dead cells by a special type of white blood cells called Z. This cleaned liquid is then put into the blood circulatory system in subclavian veins.
(c) The liquid X is somewhat similar to a component of blood. Name this component