U1 al edexcel

circulation

so as we took in the biology Ol , the heart of the mammels will have 4 chambers 2 atria and 2 ventricles which help in pumping blood all over the body parts and

oxygenated and deoxygenated blood are separated by a septum

As our body is so complex we need this mechanism which the heart works with so our Q is Why mammals have a heart and circulation

because

Mammals have a small surface area to volume ratio, they require a high nutritional intake as well as a high oxygen intake, large amounts of waste and excretory products need to be removed all at a sufficient pace, the heart is a mass transport system that provides all that and helps overcome the limitations of diffusion which by itself is insufficient.