Final answer:
Excess amounts of mitochondria are not evidence of cell injury; instead, they can indicate a cellular response to increased energy demands. Other signs like calcification, pigmentation changes, and atrophy are indicative of cell injury.
Step-by-step explanation:
The answer is: excess amounts of mitochondria. This is not evidence that cell injury has taken place.
Cell injury is typically indicated by a variety of hallmarks such as calcification of cells, indicating irreversible damage and cell death, pigmentation changes often due to the accumulation of substances within the cell or changes in cellular metabolism, and atrophy of the cell, which is a reduction in cell size due to loss of cell substance. When cells are injured, they may display certain signs such as inflammation, the formation of apoptotic bodies in the case of programmed cell death (apoptosis), or loss of plasma membrane integrity in the case of necrosis.
By contrast, an excess of mitochondria can be a cellular response to increased energy demands and not necessarily a sign of injury. In some cases, cells may increase their mitochondrial numbers to cope with heightened metabolic activities. However, it is worth noting that if the increase in mitochondria is due to a compensatory mechanism for damaged mitochondria, it can be linked to cellular stress rather than injury. Cell injury typically results in impaired mitochondrial function or structure, which is different from merely having increased numbers of mitochondria.
The evidence that cell injury has taken place include excess amounts of mitochondria, calcification of cell, pigmentation changes, and atrophy of cell. Therefore, the option that is not evidence of cell injury is none of them, as all the options provided are evidence of cell injury.