Final answer:
Skin exposure is usually expressed in terms of the amount of substance or energy per square centimeter or inch. The skin contains dense structures and is particularly vulnerable to environmental factors like sun exposure, which necessitates protection to avoid issues like skin cancer.
Step-by-step explanation:
Skin exposure to environmental factors is often measured in terms of exposure per unit area, which can be expressed as the amount of substance or energy per square centimeter or square inch for a more common and understandable reference. The skin is the body's largest organ, with impressive features, such as having 20 blood vessels, 650 sweat glands, and 60,000 pigment-producing cells packed into a 2 mm thick layer per square inch of skin. In considering skin health and issues such as skin cancer, which is linked to sun exposure and UV radiation, protective measures like the use of sunscreen and clothing are essential.
Moreover, understanding the density and complexity of the skin's structure is important when diagnosing and treating skin conditions. For example, clinical cases like allergic eczema can be directly related to skin exposure to an allergen in the environment, such as a change in sunscreen. Therefore, any sample for a skin examination should be taken considering the part of the skin that has been exposed or is symptomatic.