What issue arises when frozen tissue chips into fragments while being cut?

When frozen tissue chips into fragments while being cut, it is commonly due to the tissue being frozen too hard. This hardening occurs because the tissue is frozen at a very low temperature, which makes it brittle. As a result, when a microtome blade passes through the tissue, instead of making a clean cut, it can cause the tissue to shatter or fragment, leading to poor-quality sections that are unusable for further analysis.

In contrast, the other options do not directly address the issue of fragmentation in the same way. Moisture in the tissue could contribute to a variety of issues, but excess moisture typically leads to difficulties in cutting, such as compression or sticking to the blade, rather than fragmenting. A dull blade would cause tearing or ragged cuts rather than clean chips. Lastly, proper fixation is essential for preserving cellular structures and morphology but is not relevant to the specific problem of frozen tissue fragmentation during the cutting process.