**Core Concept**
The granular layer of the epidermis is a distinct layer of the skin that contains granular cells. These cells are involved in the final stages of keratinization, where they undergo significant changes to become the stratum corneum, the outermost layer of the skin.

**Why the Correct Answer is Right**
The granular layer is absent in the soles and palms of the hands due to the high pressure and friction in these areas. This results in a thicker stratum corneum, which is more resistant to wear and tear. The absence of the granular layer is a result of the adaptation of the skin to the mechanical stress in these areas.

**Why Each Wrong Option is Incorrect**
* **Option A:** This option is incorrect as the granular layer is not typically absent in areas with high exposure to the sun, such as the face.
* **Option B:** This option is incorrect as the granular layer is not typically absent in areas with high temperature regulation, such as the armpits.
* **Option C:** This option is incorrect as the granular layer is not typically absent in areas with high hair density, such as the scalp.

**Clinical Pearl / High-Yield Fact**
The absence of the granular layer in the soles and palms is a classic example of adaptation of the skin to mechanical stress, and is a useful fact to remember when examining the skin in patients with various dermatological conditions.

**Correct Answer:** D.