What is the purpose of placing bungs in the test tubes during experiments?

Placing bungs in test tubes during experiments serves several important functions, with a significant purpose being the prevention of evaporation of water. When conducting experiments, especially those involving liquid cultures or biochemical reactions, the presence of water is essential for maintaining the proper physiological conditions and concentrations. Evaporation can lead to an increase in solute concentration, which may affect the integrity of the experimental results. By sealing the test tubes with bungs, researchers can ensure that the liquid remains stable and the conditions within the tube are consistent throughout the experiment.

In addition to preventing evaporation, sealing test tubes with bungs also minimizes the risk of contamination from the surrounding environment. While this might not be the primary function that was considered the correct answer, it illustrates how using bungs can serve multiple purposes in experimental setups.