Answer:
The 3.9 billion year old rock has undergone three half-lives (3.9 divided by 1.3 = 3). After 3 half-lives, 12.5% of the potassium-40 remains undecayed.
Explanation:
The answer I think is B it would be same zygotes WW (widows peak)
THE CHANGE LIKELY 10 AND 30
