If you find a rock that is 1.25 billion years old, what should be the ratio of the daughter to parent?

The potassium 40 to calcium or argon 40 half-life is 1.25 billion years so if this half-life is displayed then the age of 1.25 billion years would be valid. Half life is the time it takes for an isotope to decay into half its' amount and which in the process is losing its radioactivity. 

5) protista

6) amoeba

Explanation:

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