Age of gymnosperm is
Cenozoic era
Mesozoic era
Palaeozoic era
Proterozoic era
First dinosaurs and first egg-laying mammals were originated in
The first mammals were like ...$A$... Their fossils are small sized. Mammals were ...$B$... and protected their unborn young inside the mother's body
Choose the correct option for $A$ and $B$ to complete the given $NCERT$ statement
Origin of mammal-like reptiles occurred in