Vein that transports oxygenated blood from the heart.

Who first described arteries and vein?

The windpipe is divided into two smaller tubes which are called:

The lining of the nose produces a watery liquid called :

Bronchi is divided up into many smaller tubes called:

What is the waste product of the liver?

Which gas turns calcium hydroxide solution into white or milky?

Production of which gas is an indication of respiration?

Who discovered the circulatory system?