$A$ : Mesozoic is the era of dinosaurs but they suddenly disappeared from the earth.
$R$ : Dinosaurs may have changed into birds or climatic changes killed them
Assertion and Reason both are correct and also correct explanation.
Assertion and Reason both are correct but not explanation of assertion.
Assertion is correct, but Reason is incorrect.
Both Assertion and Reason are incorrect.
Age of gymnosperm is
First dinosaurs and first egg-laying mammals were originated in
The first cellular form of life could have originated