Final answer:
Cells can end their life through senescence, apoptosis, which involves Bcl2 genes and proteins Bak and Bax, or by unregulated cell division leading to cancer.
Step-by-step explanation:
Cells can end their life cycle in a few different ways. One such method is through a process known as senescence, an irreversible state of dormancy. Another route cells can take is programmed cell death or apoptosis, which is often a part of normal development and a response mechanism to damage. During apoptosis, Bcl2 genes are transcribed leading to the production of proteins Bak and Bax, which are components of the outer mitochondrial membrane channels. These proteins facilitate the release of cytochrome C into the cytoplasm, triggering a cascade of molecular events that culminate in cell death. Additionally, cells can also progress into uncontrolled cell division, which can lead to the formation of tumors and cancers.
A process can be terminated due to various reasons, such as normal exit, fatal error, or being killed by another process. Therefore, the correct answer is option d) all of the mentioned.