Exclusive web clip - Most of us eat several times a day, but how does our digestive system actually extract energy and nutrients from this food?

Researchers say they have discovered an entirely new class of life inside the human body, and it is very similar to a virus.

Haemoglobin is bulky, so there's not much space for anything else inside the red blood cells ... around the circulatory system and digestive system in the human body, through blood vessels ...