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Describe briefly the ways how a mammalian embryo is -(i) protected (ii) nourished and (iii) how it respires. |
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Answer» (i) The mammalian embryo is protected by two sacs: (a) The chorion (b) The amnion, which contains the amniotic fluid to protect the embryo from shocks. The embryo is also protected by the thick, muscular wall of the uterus. (ii) The mammalian embryo is nourished by the nutrients which diffuse through the placenta of the mother to pass through the umbilical cord to the embryo. (iii) The mammalian embryo respires by the diffusion of oxygen through the placenta to enter the bloodstream of the embryo. The waste carbon dioxide passes through the umbilical cord and leaves through the placenta. |
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