Question

how 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

Explanation:

To determine how nicotine and tobacco cause cancer, we analyze each option:

• "By decreasing blood - sugar levels": Blood - sugar level changes are not related to cancer development from nicotine and tobacco.
• "By damaging or changing a cell’s DNA": Cancer is often caused by mutations (damage or changes) in a cell's DNA. Chemicals in tobacco (and related to nicotine use) can cause such DNA damage, leading to uncontrolled cell growth (cancer).
• "By increasing heart rate": An increased heart rate is a cardiovascular effect, not a mechanism for cancer development.
• "By increasing phlegm and mucous production": This is a respiratory symptom like in bronchitis or similar conditions, not a cause of cancer.

Answer:

B. by damaging or changing a cell’s DNA