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Geologists know that potassium-40 decays to argon-40, with a half-life of 1.3 billion years. if an analysis of a feldspar crystal in a sample of granite shows that 75 percent of the potassium-40 atoms have decayed to form argon-40, what is the age of the granite

Which question did the author of how to grow a school garden consider about the audience before writing the project plan

Heyi am new to are you all americans? ( just want to know , i don't mean any offence ) ?