Skin cells can have different characteristics depending on the context. However, the statement most applicable to skin cells, particularly keratinocytes (the primary cell type in the epidermis), is that they "have terminally differentiated."
Here's a brief explanation of the other options:
- Are stem cells: While there are stem cells in the skin (like epidermal stem cells in the basal layer), mature skin cells themselves are not stem cells.
- Become senescent quickly: Skin cells can enter a state of senescence under certain stress conditions, but this is not their defining characteristic.
- Become quiescent quickly: Quiescence refers to a state of inactivity, which is not typically a characteristic associated with skin cells.
Therefore, the most correct response is that "skin cells have terminally differentiated."