There is no specific collective noun for the noun risings; a general collective related to the context of those risings would be use. Some examples are a series of risings (armed conflicts) or a group of risings (landforms).
Gravity
the pigment in your skin
Dry skin
its dry skin
what causes skin full tickness
pigments
The same thing that causes any human to have light skin, the degree of melanin in the skin.
The ozone has a harsh affect on skin. It penetrates the skin. It also causes cancer.
UV radiation is harmful to skin. It causes skin cancer.
UVA (which causes tanning) also causes skin aging, eventually giving skin a tough leather like texture. UVB (which causes burning) also causes skin cancer, frequently melanoma an aggressive cancer that sometimes metastasizes throughout the body.
The main causes of skin breakdown in the elderly are the following; friction,urine irritates the skin because of ammonia, immobility, malnourish and etc.