Final answer:
The platypus is a monotreme, an egg-laying mammal with distinctive features including a leathery beak, found only in Australia and New Guinea. Monotremes, including the platypus and echidnas, are unique among mammals for their egg-laying reproductive method and a single opening for excretion and reproduction known as a cloaca.
Step-by-step explanation:
The correct answer is a) Platypus. The platypus is a monotreme, which is a unique group of egg-laying mammals. This group also includes another member, the echidna. The platypus is well-known for its leathery beak, and like other monotremes, it lays eggs instead of giving birth to live young. These fascinating creatures are only found in Australia and New Guinea, with the leathery-beaked platypus belonging to the family Ornithorhynchidae and the echidna to the family Tachyglossidae. Moreover, monotremes have a single opening, called a cloaca, which is used for the urinary, genital, and digestive organs. They also have a lower body temperature than most other mammals. Unlike the kangaroo, which is a marsupial, or the bat and dolphin, which are placental mammals, the platypus reproduces by laying eggs with a leathery shell.