Question

Which of the following animals have the character of both reptiles and mammals?
A. Monotremes
B. Marsupials
C. Macropus
D. Manis

Answer 1

Hint: These animals have a reptilian-like pectoral arch and egg. Despite sharing some reptilian options, they possess all the main class characteristics, like air respiration, endothermy (i.e., they're warm-blooded), exocrine gland glands, a furry body, one bone within the lower jawbone and bones within the tympanic cavity.

Complete answer: Monotremes are the novel order of mammals that features solely existing species such as Ornithorhynchus anatinus (Ornithorhynchus anatinus), the short-billed echidna (Tachyglossus aculeatus), and the western long-billed echidna (Zaglossus Bruijn). Like other mammals, monotremes possess a metameric jaw and have bones that comprise the central ear. They are hot blooded organisms. Although these animals are typically said to be primitive or ancestral, they're not ancestors of all mammals. Monotremes are egg-laying mammals, however, a simple fraction of embryonic development takes place within the womb. The embryo is nourished partly by food and partly by mucosal secretions. Monotremes feature a remarkably complicated chromosomal system that is homologous to the sex chromosome of birds. The sex determination factor SRY of mammals is absent in monotremes and ‘Sox’ is found on monotreme somatic chromosome VI. A sex chromosome-specific copy of the evolutionarily preserved opposing Mullerian internal secretion factor (AMH) has been discovered on monotreme. Therefore, these animals have the characteristics of both reptiles and mammals.
Hence, the correct answer is option A.

Note: Only two kinds of monotremes are left on the planet: the duck-billed platypuses and the four species of echidnas, or spiny anteaters. Like all mammals, they possess hair, milk, sweat glands, three middle ear bones and a brain region known as the neocortex.