Which of the following is known as the age of mammals?

Mammals evolved from therapsid reptiles in the $Triassic$ period. The type of skull in these reptiles is

Match the following columns.

Column-$I$	Column-$II$
$A.$ $500$ million years ago	$1.$ Sea weeds and few plants
$B.$ $350$ million years ago	$2.$ Jawless fishes
$C.$ $320$ million years ago	$3.$ Invertebrates

Which of the following were abundant in the $Mesozoic$ era?

Which is the oldest fossil in the evolutionary history of the horse?

$A$: $Tyrannosaurus$ $rex$ had fearsome dagger-like teeth.
$R$: $Tyrannosaurus$ was the largest dinosaur depending upon herbs and shrubs.