There is more oxygen in the air.
For seawater about 10ppb.
Oxygen enters via the lungs.
Nitrogen displaces oxygen that originally came from Earth's atmosphere. In the absence of oxygen, steel can not rust.
Lungs
magic.
oxygen \
Hydrogen, oxygen, trace minerals.
oxygen \
There is more oxygen in the air.
Fish and marine life are able to live because oxygen is soluble in water, including salt water/seawater.
Seawater and fresh water contains oxygen that fish absorb using their gill. So the substance is oxygen.
For seawater about 10ppb.
Wind and rain
Steel is corroded by the oxygen that is dissolved in water, and in the case of seawater, the process is catalysed by the salt in the water.
Dissolved salts are transported by the rivers.
yes