Dorsal and ventral blood vessels

Charles Darwin is well known for his work on natural selection. He published widely on topics ranging from barnacles to geology to plants. He travelled the...

Adaptation is an evolutionary process whereby an organism becomes increasingly well suited to living in a particular habitat. Natural selection results in helpful traits becoming more...

To most of us, one earthworm resembles another. Although earthworms do have common characteristics, species differ widely in their size, skin colour and in the roles...