UV radiation exposure is well established to cause skin cancer, premature aging, immune system suppression, and eye impairment. UV radiation is also known to be responsible for causing plants not to grow properly by preventing them from receiving enough sunlight required for healthy growth. Plants can also emit UV radiation that can damage human skin and eyes. There are two main types of ultraviolet radiation (UVR) that impact plant growth: UVA and UVB. Both UVA and UVB rays are present in sunlight, but they differ in the way they affect living things. UVB rays are more energetic and have a higher frequency than UVA rays; as such, they are better at breaking chemical bonds and causing genetic changes. But because UVA rays are less energetic they can also be absorbed by materials such as wood and glass and lead to degradation of these substances too. When plants are exposed to high levels of UVA or UVB radiation, they will usually try to protect themselves by producing more of their own protective compounds or changing how they grow. This ability allows plants to survive in areas where they would otherwise perish due to lack of sunlight.