How many oxygen atoms are needed to produce two H2O molecules

Ibelieve it is b. proton.hope my answer has you : )

The main types of electromagnetic radiation. radio  waves have  the lowest frequencies  and  longest  wavelengths, while gamma  waves have highest frequencies  and shortest wavelengths. the wavelengths vary across the electromagnetic spectrum from about 10–15 m to more than 104 m.hope it !