Supposing I can focus only on one type of material to recycle, choosing from paper (card board etc), aluminum (can etc) or plastic (water bottle etc), then which choice of material will help the environment most?
If the goal is sustainability and I can only choose one, I'd choose aluminum. Aluminum is relatively cost-effective to recycle and doesn't decompose on its own. Paper is middling efficient to recycle, and decomposes on its own — eventually. Plastic is relatively inefficient to recycle, and also doesn't decompose much on its own — which means we should avoid using it wherever possible, especially if we can't recycle it for whatever reasons.