Which item is a cylinder-shaped, calibrated container used in centrifugation to hold samples?

• A. Microcentrifuge Tube Rack
• B. Peg Rack
• C. Microcentrifuge Tubes
• D. Petri Dish

Answer: (C)

In centrifugation, you need small, cylinder-shaped, calibrated containers to hold the samples during spinning. These are microcentrifuge tubes (often called Eppendorf tubes). They are designed to be sealed and to fit securely in rotor wells, and they have graduations on the side so you can measure exact volumes before loading. The tube’s cylindrical form and built-in volume markings make it the ideal container for spinning down small volumes.

A tube rack is just a stand to hold tubes, not a container itself. A peg rack serves as a storage/organization tool, not for holding samples during spinning. A Petri dish is a shallow, flat culture dish, not a cylindrical, calibrated container suitable for centrifugation.