The root “prim ” means “first in time”, “ev” means “time”, which of the following are primeval beasts？

The root “prim ” means “first in time”, “ev” means “time”, which of the following are primeval beasts？
A.Dinosaurs
B.Mammoths
C.Elephants
D.Kangaroos
正确答案：Elephants#Kangaroos