Beauty [of] under sea can enjoy variously. One of them with scuba diving. One of [the] equipments of scuba is containing tube [of] air, used to breathe underwater. Diver has to go out to surface when supply of air has almost [used up/finished]. I have an idea which early from how fish breathe. They take underwater dissolve oxygen with gill, but after some data collecting, in the reality the amount of dissolve oxygen in water is very small, so that fall short need of human being to...