Understand why many animals have a heart and circulation (mass transport to overcome limitations of diffusion in meeting the requirements of organisms).

Many organisms are single celled organisms (e.g. jelly larvae) which obtain all nutrients through diffusion.

Mass Transport System

It contains vessels for transport where a medium is used to transport nutrients (way of moving in the right way) so a mechanical pump (such as the heart) pushes the medium or nutrients around the organism.

The surface area to volume ratio of an organism determines if…