oxidation

“On Earth, the majority of atmospheric oxygen is derived from biological activity, making the nature of surface oxidation important for understanding the potential for past life on Mars,” Loeb said.

Without bicarbonate or CO₂ present in experimental DNA oxidation reactions, the chemistry is also different.

The oxidation states of individual elements could also be determined locally.

With black tea, after the leaves are picked they're exposed to air, which leads to oxidation.

This allows electrons to be removed from the absorbed electron donors through solid-state ET oxidation reactions, resulting in the accumulation of holes in the donors inside the nanotube.