C. Mutagens causes mutations.
Okay so nothing equals nothing so after that you get nothing
Pharyngeal constrictor muscles (superior, middle and inferior)
The pharyngeal constrictor muscles are a group of muscles that form the lumen of the pharynx. After you swallow, an act that you have control, it starts a involuntary contraction by these muscles to propel the bolus downwards.
When they are breathed in, they can become trapped in the lungs and stay there for many years. Many problems might result in accumulation of such. One would be asbestosis, an inflammatory condition of lungs that can cause shortness of breath. Another would be mesothelioma, a rare cancer that affects the lining of the lungs, chest cavity, or abdomen.