D) Amphibia was considered to be the first to develop lungs
I believe it is 4)Shearing teeth (Carnassial teeth)
Amniotic egg are for reptiles
Fur are for marsupials, and dogs
Retractable claws are are cats
Shearing teeth are for carnivores
Kingdoms are classified into three Domains and into one of the six kingdoms of life.
Answer:
The Mesozoic Era is the answer
