Explain where cells come from

What protects the lining of the stomach from acidic gastric juices?

If scientists are wrong about earth's age based on radioactive material and the decay rates are really much faster, how would nuclear power plants be affected?

This question is only for applicants to scholars for medicine or scholars for dental medicine: what aspects about medicine (or dental medicine) intrigue you? describe how these aspects influence your life. (100-650 words)