The main job of capillaries is to allow the exchange of substances between blood and tissues.  π©Έ
When blood travels through the capillaries, oxygen from the blood moves into cells, while 
carbon dioxide, a waste product, moves into the blood to be taken away. This is important because our cells need oxygen to work, just like cars need fuel!  π
Capillaries also deliver nutrients, such as glucose, to the cells. This exchange happens very quickly, like a fast delivery service!  π¦
Without capillaries, our body couldn't get what it needs to be healthy!