Oxygen in its pure, gasseous form, as usually encountered on Earth is an invisible gas and cannot be seen.
Yes, pond weed produces oxygen, because it photosynthesises. The oxygen can be seen as bubbles
it is a colourless gas as are most gases
Yes, Phosphorus reacts with oxygen to produce oxides in the form of a gas. This can be seen in P4O6 or P4O10.
i have seen the cheapest price in oxygen for £2:00.
profound shock (as seen with acute myocardial infarction)
raccon
more oxygen was consumed
energy
oxygen is what makes your blood red... you may not know this but when your blood is not seen it is blue
I've seen Roseanne on Nick at Nite, TV Land and Oxygen
Bank 1 oxygen sensor is the closest to the engine exhaust manifold. It is usually can seen and replaced if necessary with open hood.
After a planetary nebula the oxygen in the middle will make it turn into a blackhole or neutron star.