Suppose you were writing a summary of the article. Which would be most important to put in the summary?

Food waste takes up space and gives off a greenhouse gas.
People everywhere use precious fresh water for crops.
Young people don't need superpowers to make a difference.
Waterbirds and fish cannot live in polluted areas.

The most important point to include in the summary would be that food waste takes up space and gives off a greenhouse gas. This highlights the negative environmental impact of wasting food.