They both contain water, ocean in a liquid form and atmosphere as water vapor and oxygen, although oceans have relatively little oxygen and difference is that the main substance in the atmosphere is various gasses, while the main substance in the ocean is water in liquid form.
Some similarities: they both contain water: ocean in a liquid form and atmosphere as water vapor and oxygen, although oceans have relatively little oxygen (but enough for the fish to catch).
Major difference is that the main substance in the atmosphere is various gasses, while the main substance in the ocean is water in liquid form.
