Question

thickened, white, leathery spots inside a smokeless (chewing) tobacco user’s mouth.
leukoplakia
carcinogens
nicotine
nds - e-cigarette
stimulant

Explanation:

Leukoplakia is defined as thickened, white, leathery patches that commonly develop in the mouth of people who use smokeless (chewing) tobacco. The other options do not match this description: carcinogens are cancer-causing substances, nicotine is the addictive chemical in tobacco, NDS-E-Cigarette refers to an e-cigarette product, and stimulant is a general category of substances that increase bodily activity.

Answer:

Leukoplakia