An isotope sample initially weighing 500 grams decays to produce a daughter element. what is the amount of parent element remaining after two half-lives?

The answer is 125 grams.

Explanation:

Elements and substances decay in time and the amount of time for it to be half of it's initial amount is defined as "half-life of that substance".

In the example, the initial weight is 500 grams and we are asked to determine the amount after two half-lives, which after the first half-life is 500/2 = 250 grams and after the second one, 250/2 = 125 grams remains from the parent element.

I hope this answer helps.

the answer would be 2, if crossing over doesn’t occur 2 out of 4 of the daughter cells will have that allele.

hope this : )