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barry barry
wrote...
Posts: 11630
12 years ago
John, a 72-year-old grandfather, had been smoking heavily for 24 years and had a persistent cough. A biopsy of his lung tissue revealed considerable amounts of carbon particles. How could this happen considering the natural cleaning mechanism of the respiratory system?
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biology101biology101
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Posts: 442
12 years ago
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barry Author
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Helped a lot
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This helped my grade so much Perfect
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