Which combining form denotes a blood clot (thrombus)?

• A. dist/o
• B. cry/o
• C. thromb/o
• D. cerebr/o

Answer: (C)

The concept being tested is recognizing the specific combining form that names a blood clot. thromb/o is the combining form that denotes a clot, as in thrombosis or thrombus, which is the clot itself. That’s why this form fits the term for a blood clot.

The other options don’t fit this meaning: dist/o refers to distance or distant, as in distal; cry/o means cold, as in cryotherapy or cryopreservation; cerebr/o relates to the brain, as in cerebral. So thromb/o is the correct root for a blood clot.