12. - 14. soruları aşağıdaki parçaya göre cevaplayınız.
Mammals have spread successfully over the entire world, and have even conquered extreme habitats such as deserts and the Arctic. In spite of all external diversities, they have numerous characteristics in common. Mammals are the most highly developed vertebrate animals. Their constant body temperature grants them a life largely independent of temperatures of the surrounding areas. They achieve constant body temperature by a high food intake ─ in comparison to reptiles, for example ─ and an increased rate of metabolism. Long respiration, typical of mammals, supplies the body cells efficiently with oxygen. The heart consists of two atria and two ventricles, which are completely separated from each other. This prevents the mixing of oxygen-rich and oxygen-deficient blood. All mammals, except for the egg-laying monotremes, give birth to live young. During pregnancy, the foetus is linked to the circulatory system of the female and is supplied with nutrients via the placenta and umbilical cord. The exchange of oxygen and carbon dioxide also takes place using this route.
12) Which of the following is true about mammals?