Extreme environments refer to locations on Earth where conditions are particularly harsh, such as extreme temperatures, high pressure, low oxygen levels, or high levels of radiation. These environments can include deserts, deep-sea hydrothermal vents, polar regions, and high-altitude mountains. Research in extreme environments often focuses on understanding how organisms adapt to survive in these harsh conditions, as well as studying the physical and chemical processes that occur in these environments. This research can provide valuable insights into the limits of life on Earth and potentially inform our understanding of potential extraterrestrial life.