biology questions

1.How do the tail structure of dinosaur different with the mammals? What is the major purpose of those tail? Is there any relationship between them?

2.Compare to the leg and feet structure of different kind of dinosaur and mammals, what is the similarities and differences between different kinds of dinosaurs and between dinosaurs and mammals? What may cause the similarities and the differences?

You will define them and explain why you choose them and why they are important in furthering our understanding of megafaunas. Then you will research what we know about the ideas in your questions to contribute some evidence to the inquiry.  In the end you do not have to answer each question fully but you must explain the current state of understanding with references, contribute some observations, and suggest what might be done next to continue the search.