Carbon monoxide has a density that is about 97% that of air under normal room temperature. So, to answer the question, no, it is lighter than air. You would think, then, that it would rise. In real-world conditions, there are a lot of forces that cause the CO to mix rather completely into the air.
Growth Hormones. Growth Hormones are responsible for the development function of the entire body. Growth Hormones are peptide hormones which encourages growth and cell regeneration in both humans and animals.
Prolactin and growth hormone act upon certain body tissues; they do not affect specific organs. Prolactin travels to the breast tissue glands of nursing mothers, causing milk production. Growth hormone stimulates protein synthesis and cell division in cartilage and bone tissue. Gigantism results when excessive amounts of growth hormone are produced during childhood.