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.
How can hormones affect the growth of breast cancer? Hormones like estrogen and progesterone are chemicals produced by glands in the body. Normally, these hormones help regulate body cycles, like menstruation. However, sometimes these same hormones can cause cancer to grow. The pathologist will perform tests on the breast cancer cells to determine if they have receptors that feed on estrogen or progesterone, stimulating their growth.