Violation

The colour of normal gingiva is affected by the 1. vascularity of the gingiva. 2. epithelial keratinization. 3. thickness of the epithelium. 4. melanin pigmentation.

(1) and (3)

All of the above.

(1) (2) (3)

(4) only

(2) and (4)

Please describe the matter of abuse