New York is much bigger than Dallas.

In the given sentence, the word bigger describes a comparison between two cities and shows a greater degree of quality.

Hence, the word bigger is a comparative adjective.

Everest is the highest mountain in the world.

In the given sentence, the word highest describes a comparison between more than two things and shows the greatest quality.

Hence, the word highest is a superlative adjective.

Edith is a better player than Christean.

In the given sentence, the word better describes a comparison between two persons and shows a greater degree of quality.

Hence, the word better is a comparative adjective.