How do the structures of different types of animals allow them to obtain energy and eliminate waste?be a long explanation

The structures of different types of animals usually  allow them to obtain energy and eliminate waste through the due course of evolution the organisms have adopted various structural changes that enables them to digest food particles and eliminate waste.

A plant growing towards sunlight is a classic example of an organism changing its morphology for the environment or its food, similarly all organisms have devised their metabolism that is fueled by the digestive system to ease their energy gaining process followed by waste removal.

oak trees? ? what was listed