I believe the answer is:
1. B. The Quarternary
During the quartenary period, continental ice sheets started to decayed and gradually gone. This made many mammals who have excellent physical structure to survive in the environment such as mammoth, saber-toothed cats, and glyptodonts started to extinct.
2. A. Plate interactions
The plate interractions on from inside the earth caused the land structure on the earth surface began to change, which lead to the creation of mountains , volcanoes, etc. When the movement of plates create friction with one another, it would most likely resulted in earthquakes on the earth's surface.
3. C. "Age of Mammals"
Age of mammals refers to the geologic age when the mammals are considered to be placed on the highest hierarchy on lands. The age started around 65 million years ago, after dinosaurs (which are reptiles) started to extinct.