Answer:
False
Step-by-step explanation:
There were several mammals during the age of dinosaurs that were contemporaries of dinosaurs.
For example –
a) Megazostrodon – Megazostrodon were the first mammal that emerged some 220 million years ago. They resembled to rats of present time, had hairy body , feed upon insects and reptiles, produce milk for their young ones and also has three kinds of teeth just like mammals.
b) Didelphodon – These mammals resembled the size of present day cat and possesses characteristics of both dinosaurs and mammals ( milk production, three kind of teeth, body hair).