This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: General pathology, Subject name: Pathology
Which of the following is typical of apoptosis? 
Select and explain. 
A. Activation of DNA synthesis, as in the mitotic cycle, B. Activation of endogenous endonucleases, C. Reduced cytosolic free calcium, D. Karyolysis
B: Activation of endogenous endonucleases
Answer: B: Activation of endogenous endonucleases 
Explanation: Apoptosis is characterized by the activation of endonucleases, which leads to DNA fragmentation. The chromatin of apoptotic nuclei appears clumped as inpyknosism, but karyolysis does not occur. Nuclei may become fragmented, but this fragmentation is distinct from the mitotic division. Apoptosis does not induce an influx of inflammatory cells, and the dead cell fragments are taken up by adjacent cells in the tissue itself. Similar to other forms of cell death, apoptosis is associated with an influx of calcium into the cytosol.