The number of people on a petit jury?

There can be from 6 to 12 depending on the case.

Individual state laws determine how many jurors usually sit on trials. Felonies usually get 12 jurors, Misdemeanor juries can have as few as 7.

The minimum number of people in a Missouri grand jury is 12 according to Article I Section 16 of the Missouri Constitution, which states: "Section 16. That a grand jury shall consist of twelve...

Correct.

A normal (petit) jury hears evidence of a case after the arrest and arraignment of the accused. A grand jury hears evidence before the case is filed and may issue indictments based on the evidence...