The layers above would be not as old and the layers below would be the older layers.
blood rich in oxygen enters the lungs through the pulmonary artery in where the alveoli within the lungs exchange carbon dioxide and oxygen so the carbon dioxide leaves your body.
Hope this helps a bit
<span>Gametogenesis is the process of forming gametes (by definition haploid, n) from diploid cells of the germ line. Spermatogenesis is the process of forming sperm cells by meiosis (in animals, by mitosis in plants) in specialized organs known as gonads (in males these are termed testes).</span>
In nondisjunction, if members of a pair of homologous chromosomes do not move apart during meiosis I or sister chromatids fail to separate during meiosis II, this means one gamete receives 2 of the same kind of chromosome and i<span>f either one of these abnormal gametes unites with a normal one at fertilization, the zygote will also have an abnormal number of particular chromosomes; which is known as an aneuploidy.</span>
