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.
A hormone (from Greek á½ÏÎ¼Î®, impetus) is any member of a class of signaling molecules produced by glands in multicellular organisms that are transported by the circulatory system to target distant organs to regulate physiology and behaviour.ne special group of hormones is the tropic hormones that stimulate the hormone production of other endocrine glands. For example, thyroid-stimulating hormone (TSH) causes growth and increased activity of another endocrine gland, the thyroid, which increases output of thyroid hormones.