The bodies of both plants and animals are incredibly complex and diverse, yet our classification schemes generally zero in on a few very specific aspects that we use to trace their anscestry and identify them. Present several examples of physical features we use to classify groups of life forms, then expand a little on why these features are considered so important (eg. the morphology of the fins on fish). What astounds you about the skeletal design for tetrapods?
At least 250 word