Answer:
What is the purpose of the text?
✔ to inform people about how to set up an aquarium
Which section should you read to learn what to buy to set up an aquarium?
✔ “Gathering Materials”
Which section should you read to understand how to set up the filter?
✔ “Keeping It Clean”
(Photo for proof below.)
Explanation:
The title "How to Set Up a Freshwater Aquarium" and the steps for how to set up an aquarium justifies the first answer.
Gathering materials tells you all the things you need in order to set up an aquarium. If you lack some items, you'll have to buy them.
The filter is a machine that keeps the tank from becoming too dirty for aquatic life to live in. That is why the title is called "Keeping It Clean", it relates to the tank filter keeping the tank clean of waste.
Here's a photo of Edge incase you're doubtful.
