What effect does increased UV radiation have on living organisms?

Increased UV radiation has a significant and detrimental effect on living organisms, primarily by damaging genetic material. UV radiation can cause mutations in the DNA of cells, which may lead to disruptions in normal cellular function, potentially resulting in cancer and other health issues. The high energy of UV rays can break chemical bonds in DNA, leading to the formation of thymine dimers, which distort the DNA structure and interfere with replication and transcription processes.

While some organisms have mechanisms to repair UV-induced damage, excessive exposure can overwhelm these systems, resulting in cellular malfunction or death. This is particularly relevant in higher organisms, including humans, where increased UV exposure can lead to skin cancers, cataracts, and immune system suppression.

The other options suggest either no effect, enhancement of growth, or improvement of immune response, which do not accurately reflect the biological consequences of heightened UV radiation. While some specific conditions might allow for certain beneficial effects of low-level UV exposure (like vitamin D synthesis), the overall impact of increased levels of UV radiation is harmful, validating that the correct response is it damages genetic material.