Name the two types of UV radiation involved in tanning.

The two types of UV radiation involved in tanning are UVA and UVB. UVA rays penetrate the skin more deeply and are primarily responsible for the aging effects of sun exposure, as well as contributing to skin tanning. They induce the production of melanin, the pigment that darkens the skin, as a response to protect deeper layers from damage.

UVB rays, on the other hand, are responsible for causing sunburn and play a significant role in the development of skin cancer. They stimulate the production of vitamin D and also contribute to the tanning process, although their effect is shorter and more intense than that of UVA rays.

UVC radiation is typically filtered out by the Earth's atmosphere and does not significantly contribute to tanning or sunburn under normal conditions. Therefore, the combination of UVA and UVB is critical when considering the tanning process and the potential effects on the skin.