**Core Concept**
The healing of wounds can occur through two main processes: primary intention and secondary intention. **Primary intention** involves the direct closure of a wound with minimal tissue loss, whereas **secondary intention** involves the healing of a wound with significant tissue loss, requiring granulation and contraction.

**Why the Correct Answer is Right**
The most important factor determining whether a wound heals by primary or secondary intention is the presence or absence of a significant tissue gap. If the wound edges can be approximated, **primary intention** healing can occur, with direct closure of the wound. However, if there is significant tissue loss, the wound must heal by **secondary intention**, involving the formation of granulation tissue and wound contraction.

**Why Each Wrong Option is Incorrect**
**Option A:** Incorrect because the size of the wound, while important for overall healing time, does not solely determine the healing process.
**Option B:** Incorrect as the location of the wound can affect healing due to varying blood supply but is not the most critical factor in determining primary vs. secondary intention.
**Option C:** Incorrect because, although infection can significantly impact the healing process, it does not determine whether a wound heals by primary or secondary intention.
**Option D:** Incorrect as the depth of the wound can influence the healing process but is not the primary factor in deciding between primary and secondary intention healing.

**Clinical Pearl / High-Yield Fact**
A key point to remember is that wounds with significant tissue loss or those that cannot be closed primarily are more likely to heal by **secondary intention**, which often results in a larger scar and potentially longer healing times.

**Correct Answer:** D. The extent of tissue loss.