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.
In addition to assisting with production thyroid hormones, selenium is also critical in the regulation of thyroid hormonal levels. Several of the enzymes arranged around selenium are key factors in assuring that thyroid hormone levels remain balanced.