What is the function of a peg rack in a laboratory?

The function of a peg rack in a laboratory is primarily to dry laboratory glassware. When glassware such as beakers, flasks, and test tubes are washed, they need to be dried thoroughly before being reused to prevent contamination and ensure accurate experimental results. A peg rack provides a convenient structure where the glassware can be inverted on pegs, allowing for efficient drying by enabling air circulation.

While the other options describe important functions in a laboratory context, they do not specifically pertain to the primary function of a peg rack. For example, supporting microscopes during use is typically the role of a sturdy table or a dedicated stand, while test tube holders or racks are used specifically for holding test tubes securely. Similarly, the organization of chemicals requires shelving or cabinets with appropriate labeling and containment rather than a peg rack. Thus, the peg rack's design and purpose are uniquely suited for the drying of glassware, making it the correct answer.