Where does thyroxine come from and what does it do?

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.

b. regulated is the actual answer to your question.

explanation:

carbohydrates: (starches and sugars) composed of carbon, hydrogen, and oxygen.

lipids: (fats, oils, and waxes) are made of carbon and hydrogen atoms.

nucleic acids: contain hydrogen, oxygen, nitrogen, carbon, and phosphorus. they are polymers of nucleotides. a nucleotide has three parts, a 5-carbon sugar, a phosphate     (-po⬇️4) group, and a nitrogenous base.

proteins: made up of nitrogen, carbon, hydrogen, and oxygen. they are polymers of amino acids.