Different radioactive isotopes have different half-lives (which is the amount of time taken for half of the total isotopes in the material to decay). Therefore, to predict the age of a rock in radiometric dating, the initial amount of the isotopes is determined and then that of decayed ones is determined. The predictability of the half-lives of the elements is then used to determine the age of the rock/fossil.
<span>B.The amounts of carbon-14 and nitrogen in sedimentary rocks are measured.</span>
Radioactive dating is a method of dating rocks and minerals using radioactive isotopes. This method is useful for igneous and metamorphic rocks, which cannot be dated by the stratigraphic correlation method used for sedimentary rocks.
Two hormones are primarily responsible for pubic hair during puberty. Androgen and Estrogen, of which are spectively provided by the "Testes and Ovaries". Pubic hair is the bodies attempt of protecting those organs against friction with contact of skin.
