Science - Human Body

As blood circulates through the body, which gas is picked up which is of no use to the body? 

What does blood deliver to the cells in organs, muscles, bones and nerves? 

Name two ways to prevent many chronic lung and respiratory illnesses: 

What is the heart doing as it beats? 

Without this gas, the body’s cells would die: 

How are dead blood cells removed from the body? 

What happens to your heart rate when you exercise? 

What is the liquid part of the blood called? 

What are white blood vessels designed to do? 

What is the difference between an artery and a vein?