How is your life expectancy due to both genes and the environment?

Life expectancy is affected by both genes and environment because; 1) one could have genetic underlying health issues that could cause an untimely demise, and 2) the environment in which they live could have uncontrollable events which may shorten one's life, such as violence, limited access to health care, and pollution.

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i guess you forgot putting 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.