Where might undamaged cells be found when preparing a sample of fragile cells using a combination technique?

When preparing a sample of fragile cells using a combination technique, the undamaged cells are typically found on the first third of the slide where the cells were spread. This area is crucial because it is where the initial contact occurs while the specimen is being smeared.

During the preparation, the goal is often to gently spread the cells to minimize damage, particularly with fragile specimens. The first third of the slide generally allows for a more uniform distribution of cells without over-compression, which can occur if too much pressure is applied or if the spreading is extended too far. This gentle technique helps in retaining the integrity of the cells, thus increasing the likelihood of finding undamaged cells in this area.

In contrast, other areas of the slide may either exhibit more damaged cells due to excessive force, or may not have sufficient cells for assessment. For instance, the untouched center would not contain cells at all since it is not spread, and the last third may be too thin or unevenly distributed to provide a reliable sample. The edges of the smear could likewise suffer from dragging or shearing forces that result in greater cell damage. Therefore, the first third is identified as the ideal location for undamaged cells in this context.