Final answer:
The question concerns the genetic variability in the enzyme acetaldehyde dehydrogenase (ALDH) that metabolizes acetaldehyde. While an exact percentage of the population with low or inactive ALDH is not provided, it's known that significant interindividual and interethnic differences exist.
Step-by-step explanation:
The question is related to the genetic variation in the activity of acetaldehyde dehydrogenase (ALDH), which is an enzyme involved in the metabolism of alcohol. The ALDH enzyme converts acetaldehyde, a toxic metabolite formed during the detoxification of alcohol in the liver, into acetate, a non-toxic molecule. It is well-known that there is significant interindividual and interethnic variation in the activity of ALDH, which can affect a person's capacity to metabolize alcohol.
Based on the information provided, we are looking for the percentage of a certain population that has a low or inactive form of ALDH. The correct answer is not explicitly stated in the provided information, so you would need to check reliable sources for a precise percentage. However, considering the context of genetic variability in metabolic capacity, it becomes relevant to understand that such variations can be substantial, as seen in cases where there is a 40-fold difference in metabolism capacity for certain substances.