A great deal of the knowledge of the body's anatomy and functions can be traced to scientific findings from animal research. Comparing different species and studying the differences and similarities between them is one way to gain insights. Even simple animals can be used to study complex biological systems such as the nervous or immune systems, which follow the same basic organisation and function in all animals.For example, much has been learnt about the function of neurons from studying the giant squid axon.Information from this sort of work can then be applied to higher animals and humans.