Grass-> rabbit-> snake-> eagle in this food chain, what is the role of the snake?

The snake is a tertiary consumer. It will eat smaller prey like rabbits.

i believe it is "they are not used up by reactions" as the answer to your question, text me back if this is correct because i just learned this.

if you look up in the top right corner you'll see your current profile picture, click than click "view profile" you'll be able to change it there.