Final answer:
The olly or dry conditions of the skin that cannot be permanently changed, only improved with treatments, are determined by the epidermis of the skin.
Step-by-step explanation:
The olly or dry conditions of the skin that cannot be permanently changed, only improved with treatments, are determined by the epidermis of the skin. Skin conditions like oily or dry skin that persist over time are primarily determined by the characteristics of the skin's outermost layer, the epidermis (option a). The epidermis contains cells that produce sebum, an oily substance that helps lubricate the skin. The amount of sebum production, influenced by genetic factors and hormonal changes, contributes to skin texture. While treatments can help manage these conditions, the underlying characteristics are often inherent. The dermis (option b), subcutaneous tissue (option c), and sebaceous glands (option d) also play roles in skin health but are not the primary determinants of whether the skin is oily or dry.