Samarium has a half-life of approximately 106 billion years. if you found a sample of samarium from the beginning of earth's history, approximately 4.6 billion years ago, which would be the best approximation of the amount of parent isotope left in the rock?
a nearly 100 percent
b 50 percent
c 25 percent
d less than 10 percent
brainliest for the correct answer and 20 pts~!

4.3 billion years is only 4.3% of the time it takes for half of the Samarium to decay, so we would expect nearly all (100%) of the parent isotope to still be present after that short (? ! ?) an amount of time.

A) Nearly 100 percent

Explanation:

As we know that the amount of radioactive substance is given at any time by the equation

here we know that

we know that

now radioactive constant is given as

now number present after t = 4.6 billion years

so it is approximately 97% amount is left after given time

so correct answer would be

Nearly 100 percent

gets less

they should be similar or the same