The golden age of dinosaurs was in which of the following eras?

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

The origin of seeds in land plants was achieved about $345 \; \text{million}$ years ago, in lineages recognized as ancestral to all more advanced vascular plants in:

Dinosaurs were abundant in

From which group did the $Prototheria$ evolve?

The biggest dinosaur had about $20$ feet height and huge, fearsome dagger-like teeth. The name of it is