We have discussed that the human body has trillions of cells. We also discussed that each cell gets oxygen and nutrients from the food we eat.

How do the nutrients reach the cells? There are trillions of them, so, we will need a vast network to do it.

Imagine a city with trillions of bus stops and buses that need to always be travelling! Even building a transport network with 100 bus stops is difficult. But, our bodies have somehow connected trillions of them. Let's find out how!