Which of these substances can be used to prevent overspreading of chromosomes in hypotonic solutions?

Reducing the drying time is the correct approach to prevent the overspreading of chromosomes in hypotonic solutions. When cells are placed in a hypotonic solution, they swell due to the influx of water, and this swelling is essential for chromosome spreading during cytogenetic analyses. However, if the drying time is prolonged, the chromosomes can spread and overlap excessively, making it difficult to analyze them accurately. By reducing the drying time, chromosomes can be fixed before they have a chance to overly spread, allowing for clearer visualization and better preservation of their structure for analysis.

In contexts where this technique is employed, maintaining an optimal environment for chromosome spreading is crucial. Adjusting drying times helps strike a balance between adequate chromosome separation and preventing excessive overlap, contributing to more reliable karyotyping results.