A-LevelBiologyGas exchange9700/12 · Oct/Nov 2018 · Q341 Mark
Cigarette smoke contains tar. Which statements describe the effect of tar on the respiratory system? 1 Tar causes goblet cells to increase the secretion of mucus. 2 Tar increases the risk of blood clots forming inside blood vessels. 3 Tar may cause changes to the DNA in epithelial cells.
A1, 2 and 3
B1 and 2 only
C1 and 3 only
D2 and 3 only
✓ Correct answer
C: 1 and 3 only
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