From the following statements, select all that are consistent with primary lactose intolerance.

Primary lactose intolerance is more common in some ethnic groups

If a person has lactose intolerance, consuming any amount of lactose containing product will cause symptoms.

Primary lactose intolerance is generally reversible.

Diarrhea is caused by the osmotic effect of lactose in the large intestine.

Primary lactose intolerance is often seen in Crohn's disease.

Symptoms of primary lactose intolerance include gas, bloating, and diarrhea.