Which of the following is NOT a primary factor affecting alcohol distribution in a subject?

The age of the subject is considered a secondary factor rather than a primary factor affecting alcohol distribution. The factors primarily influencing how alcohol is distributed throughout the body include a person's weight, body fat percentage, and gender.

Weight is crucial because a heavier person typically has more body water, which can dilute alcohol, leading to a lower blood alcohol concentration (BAC) for a given amount of alcohol consumed compared to a lighter person. Body fat percentage plays a role since alcohol is water-soluble, and individuals with higher body fat percentages may have less body water, leading to a higher concentration of alcohol in the blood.

Gender is significant due to physiological differences; females generally have a higher proportion of body fat and lower body water content compared to males, resulting in women often having higher BACs than men after consuming the same amount of alcohol.

While age can affect metabolism and the body's response to alcohol over time, it does not directly influence the distribution of alcohol in the same way that weight, body fat percentage, and gender do, making it the correct choice for the question.