Question of the Day #9 · April 1, 2026
What is the only part of the human body that is unable to repair or heal itself?
Show answer
Teeth
Mature tooth enamel has no living cells, so enamel that has been lost cannot regenerate, although early mineral loss can be reversed through remineralization. Enamel is also the hardest substance in the human body, helping teeth withstand biting and chewing.