Answer: Clamp
Step-by-step explanation:
A test tube clamp or test tube holder is a instrument typically used in chemical and biology laboratories. It is used for holding the test tube while conducting the experiment. It is a safety precaution measure to use the test tube clamp to prevent accidentally injuries like burns. The test tubes may be hot or cool cannot be held by hands hence, the use of test tube clamp is suggested. It helps in holding the test tube while conducting the experiment like mixing of chemicals, heating and keeping in refrigerator.
On the basis of above description, a clamp can be useful piece used as a lab equipment that can be used to transfer the test tube from the rack into the beaker of hot water.