Theory question 104
Reproduction in Animals(a) What is sexual reproduction?
(b) State five functions of the placenta and four functions of the umbilical cord of a mammal
(c) List four types of placentation in flowering plants
(d) State four conditions necessary for seed germination.
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(a) Sexual reproduction is the production of new individuals by the fusion of male and female gametes (fertilization) to form a zygote.
(b) Placenta (any five): lets oxygen pass from mother to foetus; lets digested food pass to the foetus; lets carbon dioxide and urea pass from foetus to mother; passes antibodies to the foetus; keeps the two blood systems apart (protects the foetus from the mother's high blood pressure and some germs); makes hormones such as progesterone; attaches the foetus to the uterus wall.
Umbilical cord (any four): joins the foetus to the placenta; umbilical vein carries oxygen and food to the foetus; umbilical arteries carry carbon dioxide and wastes to the placenta; carries antibodies to the foetus; allows the foetus to move freely in the amniotic fluid.
(c) Any four: marginal; axile; parietal; free central; basal.
(d) Water (moisture); oxygen (air); suitable (warm) temperature; a viable embryo (and end of dormancy).
Keep placenta and umbilical cord functions in separate lists.