Answer:
The cilia is one of the things that act defensively in the respiratory system.
Explanation:
It propels a mucus-like liquid that covers the airway which traps pathogens (potentially infectious microorganisms) and other particles, preventing them from reaching the lungs.
Explanation:
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Answer:
Over our lifetime, our DNA can undergo changes or mutations that result in differences in the DNA sequence and may affect the proteins that are made. Mutations can occur as a natural consequence of errors in DNA replication or as a result of exposure to environmental factors such as smoking, sunlight or radiation.
Explanation: