Why were protozoan cysts barely visible in a permanent stained smear?

In permanent stained smears, poor fixation can significantly impact the visibility of protozoan cysts. Proper fixation is crucial as it preserves the morphology of the organisms and ensures that the staining process effectively highlights the cysts. If fixation is inadequate, the cysts may not adhere well to the slide or may be altered in their structure, leading to a diminished or obscure appearance under the microscope.

In this context, the visibility of protozoan cysts relies heavily on their structural integrity and adherence to the slide, both of which are compromised by poor fixation. This makes the correct choice significant in understanding why cysts might be barely visible in stained preparations. Proper fixation enhances the likelihood that the necessary details needed for identification will be preserved and visible when viewed under the microscope.