Which of the following items helps secure items to a stand during experiments?

The iron ring is specifically designed to be clamped onto a stand (like a ring stand) and serves as a support for various apparatuses during experiments. It's commonly used in laboratory settings to hold items such as beakers, flasks, or other glassware securely in place, allowing for stable and controlled experimental conditions. By providing a reliable anchor point, the iron ring helps facilitate safe and effective experimentation, reducing the risk of spills or accidents.

Other items listed serve very different functions; for example, a cork borer is used for cutting holes in materials like cork, while a measuring pipette is used for accurately dispensing liquids. A first aid kit is essential for safety and medical emergencies but is unrelated to securing items in a lab setting. Thus, the iron ring is the most relevant tool for that purpose.