Which of the following statements is true regarding the cell cycle?

The statement that not all cells undergo the cell cycle is true because there are certain types of cells in the body that exit the cell cycle and enter a quiescent state known as G0. In this phase, cells are metabolically active but do not reproduce or divide. Examples include differentiated cells like neurons and muscle cells, which are generally considered permanent non-dividing cells. This illustrates that while many cells do actively go through the cell cycle to grow and repair tissues, there are those that do not divide at all throughout their lifespan.

The other statements either overgeneralize cellular behavior or relate specifically to pathological conditions. For instance, saying that all cells in the body complete the cycle every year is misleading, as many cells can remain in G0 for extended periods without dividing. The claim that only cancer cells lose regulation of the cell cycle is also incorrect; normal cells can lose regulation under stress or mutations, leading to other issues apart from cancer. Lastly, the assertion that all cells go through the cell cycle continuously fails to account for those in G0, which do not actively participate in cell division.