Which chronic disease may be prevented by regular visits to the dentist? a. emphysema b. obesity c. allergies d. oral cancer

 The answer is D.)oral cancer

Hi, D. oral cancer would be your answer. 

Emphysema has nothing to do with your oral health, it's a disease that makes it hard to breathe and blocks air flow
Obesity has something to do with excessive body fat that can cause health problems, but not dental ones. 
Allegeries has nothing to do with oral health either. 
Oral cancer would be your answer because it has something to do with your oral health. It's cancer that's in your mouth. 

The answer is sensory neruon