Final answer:
The correct answer to the student's question about the term for tiny pinpoint hemorrhages caused by unburned powder from a firearm is tattooing, which is different from petechiae.
Step-by-step explanation:
The tiny pinpoint hemorrhages that result from the discharge of unburned powder being deposited into the skin are called tattooing. This is not to be confused with petechiae, which are small red or purple spots on the skin resulting from blood leaking out of damaged vessels. Tattooing in a forensic context refers to the marks made on the skin by gunpowder and other debris that can occur when a firearm is discharged at close range to the skin. The term is also used to describe the skin adornments created with ink and needles, but in the context of firearm injuries, it refers to this specific forensic evidence.