Thyroxine is an important hormone released into the bloodstream by the thyroid gland in the body. When tyroxine is released into the blood stream, it moves through certain organs such as the kidney and liver, where most of it is changed to an active form known as triiodothyronine. Thyroxine perform important roles in brain development, heart and digestive functions, bone maintenance, controlling muscle and metabolic rate of the body.
There are lots:
Biology and Medicine - cloning and expression of human insulin in bacteria (stopped having to produce it from pig pancreases); Watson & Crick discovery of the structure of DNA; gene therapy in humans
Chemistry - determination of the exact number of molecules in a mole (Avagadro's number); discovery of radioactivity (Rutherford); the invention of nylon (DuPont); Boyle's law (behavior of gases)
Phylum, it is the second largest group.
