Dinosaurs:A. went extinct at the end of the CretaceousB. were archosaurs

C. may have had some degree of endothermy (a way to control body temperature) D. all of these

Option (D)

Explanation:

Dinosaurs are the extinct species that were very well structured and developed and were enormous. They existed on earth during the Mesozoic era, which includes the Triassic, Jurassic and Cretaceous period and the rocks of this age are found to comprise of their fossils at different places on earth. They were extinct about 65 million years back i. e. by the end of the Cretaceous.

They were Archosaurs, which belongs to the group of diapsid amniotes and are mainly classified as reptiles. They also had some property of endothermy, where an organism can maintain their body temperature by carrying out the processes related to metabolism. So, they were able to control their body temperature.

Thus, the correct answer is option (D) - all of these.