Which category of cells is described as constantly undergoing the cell cycle?

Skin cells are constantly undergoing the cell cycle due to their high turnover rate. This is essential for maintaining the protective barrier that skin provides against environmental damage and pathogens. Skin cells are continuously shed and replaced, making it vital for them to divide and replicate regularly through processes like mitosis.

In contrast, muscle cells typically have a very limited capacity for division after they have fully differentiated, as they are specialized cells that focus on contraction rather than proliferation. Neurons are also largely post-mitotic, meaning they do not generally divide after development to form new neurons. Adipose cells, while they can divide, do not do so at the high rates observed in skin cells, as their primary function relates to storage and energy regulation rather than continuous renewal. Therefore, skin cells are the category that exemplifies constant cycling through the cell cycle, driven by the need for regular replacement and repair.