Bernardo is purchasing a 9-millimeter gun. What does the 9-millimeter represent?

A.
the size of the safety
B.
the grooves of the gun
C.
the size of the trigger
D.
the caliber of the gun

D. the caliber of the gun

Henrietta has found bones in an open field. She needs to find an expert to help her identify what she has found. Who is the BEST resource for Henrietta to contact for assistance?

A.
a forensic pathologist
B.
a forensic anthropologist
C.
a forensic psychologist
D.
a forensic entomologist

B. a forensic anthropologist

The correct answer is D. the caliber of the gun.

To understand what the 9-millimeter represents, we need to understand what caliber means in the context of firearms. Caliber refers to the internal diameter of a firearm's barrel, specifically the diameter of the bore (the hollow part of the barrel through which the projectile travels).

In this case, the 9-millimeter refers to the diameter of the barrel, measured in millimeters. So when Bernardo is purchasing a 9-millimeter gun, he is buying a firearm with a barrel diameter of 9 millimeters.

Therefore, option D, the caliber of the gun, is the correct answer.