Input: Identify the most salient words:

respond to environment when an organism reacts to changes in their surroundings .

Output: change
environment
organism
react

Input: Identify the most salient words:

A train comes down the tracks and enters the tunnel.

Output: come
track
tunnel

Input: Identify the most salient words:

image of a pregnant student reading in a library

Output: image
library
student

Input: Identify the most salient words:

A cat sleeping in a piece of gray luggage.

Output:
luggage
piece
sleep