WHY do humans have 32 teeth? Geneticists have theorized that our
ancestors originally had 44 teeth each. The reason was that
they consumed mostly solid foods. Subsequently, due to the fact that the human diet has become dominated by soft foods,
the size of the lower jaw decreased, and there was not enough space for molars.
So they sometimes remain in their infancy, and sometimes they erupt incorrectly and break down quickly. Nowadays, we don't consume that much coarse food,
and 20-22 teeth are enough to process it.
