Question

which practice can help prevent many diseases?
eating foods rich in gluten
getting blood transfusions
avoiding tobacco products
taking calcium supplements

Explanation:

• Eating foods rich in gluten can cause problems for people with celiac disease or gluten - sensitivity, not prevent diseases.
• Getting blood transfusions has risks like transfusion - related reactions or transmission of certain infections (though rare with proper screening), not a preventive measure.
• Avoiding tobacco products is a well - known preventive measure as tobacco use is linked to many diseases like lung cancer, heart disease, etc.
• Taking calcium supplements is mainly for bone health (in cases of deficiency), not a broad - spectrum disease prevention like avoiding tobacco.

Answer:

avoiding tobacco products