Read the passage below.

Did you know that crocodiles tend to have longer, pointed, V-shaped snouts while alligators generally have wider, rounder, U-shaped snouts?

The signal word “while” serves what purpose?

It signals a similarity between alligators and crocodiles.
It signals a difference between alligators and crocodiles.
It signals that more information about crocodiles follows.
It signals that the reader is nearing the end of the text.