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

First mammals appeared around

Find out through internet and popular science articles whether animals other than man have self-consciousness.

Birds and mammals in geological development of earth arose in period

First mammals appeared in the period