Osmium is the least abundant stable element in the earth's crust and is the densest stable element. It is found in the alloys osmiridium and iridiosmium and as an uncombined element. Osmium was first discovered by Smithson Tennant in 1803.his compound forms spontaneously when pure osmium metal is in contact with air, and is both volatile and extremely toxic, and thus the pure metal is rarely used. Osmium is, however, the most dense naturally occurring element and imparts hardness when used in metal alloys.
2 ROLES OF SEX HORMONES: 1) organizational effects - permanent, influence brain and sex organ development. 2) activational effects - occur later in life, after development of sex organs. SEX ORGAN. gonads - testes or ovaries, first to develop. internal sex organs - precursors for male and female present in embryo.
Dunn is an associate of the Center for Investigative Reporting. Hormones are chemical messengers that travel throughout the body coordinating complex processes like growth, metabolism, and fertility. They can influence the function of the immune system, and even alter behavior.Before birth, they guide development of the brain and reproductive system.ignaling ends when the circulating hormones are broken down and excreted by the body. Hormone disrupting chemicals, or endocrine disruptors, can act at any point along this hormone signaling pathway. Some are hormone mimics: they bind the receptor and send a false signal-one not commanded by the brain.