| Hormones | Chemical Nature |
|---|---|
| A) Insulin | IV) Protein |
| B) Estrogen | I) Steroid |
| C) Oxytocin | II) Peptide |
| D) Thyroxine | III) Amine |
Match the hormone with its site of production:

What is the empirical formula of a compound containing 40% sulfur and 60% oxygen by mass?