Hiking is eco friendly because when people hike, they don't need things that will pollute the air, hiking means walking up and down the mountain, or walking in the forest, so it won't pollute the world.

Kayaking is eco friendly because when you kayak, there isn't thing required to pollute the world for example, we don't need gas to kayak and it is also a very good thing to do.

Cycling does not need oil, and other stuff that will pollute the air, cycling is just riding on a bicycle.