The Company(Season 7, Episode 20) ION. Morgan's missing cousin, Cindi, reappears, and Morgan must come clean about a lie he told concerning her. In addition, the BAU reopens the investigation into Cindi's disappearance.
Selenium in biology. Although it is toxic in large doses, selenium is an essential micronutrient for animals. In plants, it sometimes occurs in amounts toxic as forage, e.g. locoweed. Selenium is a component of the amino acids selenocysteine and selenomethionine.
Selenium is still used in a few types of DC power surge protectors and one type of fluorescent quantum dot. Selenium salts are toxic in large amounts, but trace amounts are necessary for cellular function in many organisms, including all animals. Selenium is an ingredient in many multivitamins and other dietary supplements, including infant formula.