Lisa is a 19-year-old college student who recently began experiencing symptoms of lactose intolerance. She recognizes the importance of consuming adequate dietary calcium but does not want to further aggravate her gastrointestinal system.

Lactose intolerance is a disease caused by the inability to digest lactose, a sugar found in milk.

Explanation:

People suffering from lactose intolerance may have one or several symptoms simultaneously. These discomforts are triggered after the ingestion of milk, its derivatives or products containing lactose. These are:

Sickness

Abdominal pain

Abdominal swelling

Abdominal sounds or borborigmos

Abdominal distension

Diarrhea

Gas

Stool with foul odor

Weightloss

Constipation due to decreased bowel motility

the answer is:

carbon dioxide