Final answer:
European ethnic groups and some populations in Southern India tend to have a low prevalence of lactose intolerance due to genetic factors that allow adult individuals to produce lactase, the enzyme required for lactose digestion.
Step-by-step explanation:
The ethnic groups that have a low prevalence of lactose intolerance include most Europeans and people with European ancestry. Factors contributing to this include a genetic mutation that allowed European ancestors who could digest lactose to have a nutritional advantage, leading to the prevalence of lactose tolerance in these populations. Moreover, some populations in India, such as those from Southern India, also demonstrate a higher rate of lactose tolerance.
In contrast to European populations, Asian populations often have a higher prevalence of lactose intolerance. This intolerance increases with age in most mammals, but in some human populations, specifically Caucasians, the ability to produce lactase is maintained into adulthood.