Lactose intolerance causes stomach ache, gas, nausea and other gastrointestinal discomfort after ingestion of milk and dairy products. These symptoms result from the body's total or partial inability to produce lactase, an enzyme that breaks down lactose, the sugar in dairy products. As a result, the compound accumulates in the gut and is fermented by the bacteria that live there, causing discomfort.
Ice cream is a food that has a lot of milk in its composition. A person who has lactose intolerance would experience one or all of the symptoms after eating an ice cream, like Maria who feels nauseous after eating the ice cream.
The answer is Genes on the same chromosome are sometimes inherited disparately. I had the exact same question and that was the answer hope this helped! Have a good day!
