Who does a jury consist of?

12 citizens drawn from the pool of registered voters in the area who actually answered the summons, and screened by the court officers for suitability to accept the judge's instructions and not have any undesireable bias or beliefs.

The potential jurors will have a variety of options for being excused, such as being in various professional fields, handicapped, undue burden, etc.

The defense attorney will get to screen the remainder for a further winnowing. What's left after that is the jury.