Answer:

"mercury." Mercury is a naturally occurring element that is found in various forms in the environment, including in soil, water, and air. It can also be released into the environment through human activities such as mining and burning of fossil fuels. Mercury can enter the human body through ingestion of contaminated food or water, inhalation of mercury vapor, and skin contact. Exposure to high levels of mercury can cause serious health problems, including damage to the brain, kidneys, and nervous system.