Which of the following
describes the decay rate for
two different radioactive
isotopes?

https://chem.libretexts.org/Courses/University_of_Missouri/MU%3A__1330H_(Keller)/21%3A_Nuclear_Chemistry/21.4%3A_Rates_of_Radioactive_Decay

Explanation:

here is some info about it

c) 50% there are four chromosomes. after crossing over, 2 of the four have been changed. that means any gamete has a 2 in 4 chance or 50% chance of receiving the mutated chromosome.