A man is rushed to the ER after he falls to the ground and stops breathing. Doctors discover that he has a serious lung disease. Which of the following might be responsible for the disease?

Mutated DNA can change how lung cells function or reproduce, potentially damaging the lung tissue and causing disease. The choice “the cells that make the lung tissue have mutated DNA” is therefore a possible cause. Having organelles or being the right size and shape does not by itself explain a serious lung disease, and healthy cells would not be responsible.

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