Water is found in lakes and rivers. Its purpose in nature is to hydrate animals
Hydrogen gas is not abundant in nature, but hydrogen is abundant in water. Hydrogen (bonds) help ice float. Otherwise, freezing lakes would kill animals (it actually doesn't since the ice creates a "coat" above the water").
Ammonia is nitrogen-rich molecules that plant uses to get their nitrogen. It comes from the part of the nitrogen cycle where dead plants and animals are decayed.
Carbon dioxide is what we exhale. Plants "inhale" carbon dioxide and use that for photosynthesis.
Hydrogen sulfide is emitted by volcanoes and by anaerobic (oxygen-less) decay from bacteria.
Have an awesome day! I hope this helps.
