Study the data below. This is another indirect test of lactase activity in several college students. After drinking milk, if the lactose is not digested it is available for fermentation by intestinal bacteria, creating hydrogen gas. Excess hydrogen will be expelled with the breath and can be measured. Which student(s) would be lactase persistent, meaning they are lactose tolerant since they have the mutation to produce lactase and digest lactose as adults? Select all that apply. Lisa Dan Cindy Brian.