How much of the earth’s water is usable as a freshwater resource?

Earth contains about 91.9% of water but only 71% is usable as a freshwater resource. The 91.9% includes the water in the atmosphere that you can't see, like water in clouds, water as complete gas form, and water as ice.
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Argon, carbon-14, and carbon-12

That is false the sun’s core does not fusion