Oxygen-16 and Carbon-12 are stableisotopes of elements O and C respectively. Hence, they do not have half-lives. But Carbon-14 andUranium-238 are radioactive isotopes. Among them Carbon-14 has relatively short half-life as about 5730 years while Uranium-238 has a long half-life as about 4.5 billion years.
Answer is. uranium-238
1. Oxidized
2. Reduced
3. Glucose
4. Pyruvate
5. NAD+
6. NADH
An acronym for understanding gain and loss of electrons is OIL RIG (Oxidation is Loss of electrons, Reduction is Gain of electrons).
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