Ow do nicotine and tobacco cause cancer? by decreasing blood-sugar levels by damaging or changing a cell's dna by increasing heart rate by increasing phlegm and mucous production

Answer

By, damaging or changing a cell's DNA

Explanation

A cigarette smoke contains chemicals including tar that affects the lungs. Tar in the lungs can build up into higher amounts and cause shutdown of cilia motion which could cause swelling of the airways. This damage to the lungs may cause a tumor to develop due to changes that occur in the DNA  of that individual leading to cancer.

answer; indirect elisa;