Question: "Which ethnic heritage is more lactose intolerant: those of east Asian descent or those of Northern European descent?"

Context: "Lactase is an enzyme that breaks down the disaccharide lactose to its component parts, glucose and galactose. Glucose and galactose can be absorbed by the small intestine. Approximately 65 percent of the adult population produce only small amounts of lactase and are unable to eat unfermented milk-based foods. This is commonly known as lactose intolerance. Lactose intolerance varies widely by ethnic heritage; more than 90 percent of peoples of east Asian descent are lactose intolerant, in contrast to about 5 percent of people of northern European descent."

Answer:
east Asian descent
The answer is east Asian descent, based on the context that lactose intolerance varies widely by ethnic heritage and more than 90% of peoples of East Asian descent are intolerant..