When serving two guests the same amount of alcohol, if one appears more intoxicated, what could be a reason?

All of the listed factors—differences in body weight, tolerance levels, and metabolism—can significantly influence how individuals respond to the same amount of alcohol, leading to variations in perceived intoxication.

Body weight plays a crucial role because a person with a lower body weight may experience stronger effects from alcohol compared to someone with a higher body weight, due to the smaller volume of blood and tissues for the alcohol to distribute into.

Tolerance levels are another important factor. Individuals who frequently consume alcohol may develop a higher tolerance, enabling them to process and offset the effects of alcohol more effectively than someone who drinks less often. This can cause variations in how intoxicated they appear, despite consuming the same quantity.

Metabolism further complicates the scenario. The rate at which a person metabolizes alcohol can vary based on numerous factors, including genetics, liver health, and medication interactions. A person with a faster metabolism may process alcohol more quickly and thus may not show the same level of impairment as someone with a slower metabolism after drinking the same amount.

Since all these factors can impact how intoxicated a person appears, the answer that encompasses all of these aspects is indeed the most comprehensive.