The type of selection where traits in the middle range are favored is

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.

c.           is the correct answer

bal is blood alcohol level. bac will normally be higher in a person with more body fat. so the answer to your question would be, as body fat decreases, the increasing rate of bal decreases.