Question

One of the following is an egg-laying mammal:

• A. Macropus
• B. Balaenoptera
• C. Panthera tigris
• D. Ornithorhynchus

Hint:

Monotremes like the platypus and echidna are the only mammals that lay eggs.

Answer 1

The Correct Option is D

Step 1: Understanding Mammalian Reproduction Types.
Mammals are typically divided into three categories based on their mode of reproduction: monotremes, marsupials, and placental mammals. Monotremes are the only mammals that lay eggs. 
Step 2: Identifying the Animals Listed.
Macropus includes kangaroos and wallabies, which are marsupials, not egg-layers.
Balaenoptera includes the blue whale and other large whales, which are placental mammals.
Panthera tigris, or the tiger, is also a placental mammal.
Step 3: Recognizing the Correct Answer.
Ornithorhynchus, known as the platypus, is one of the few monotremes alongside echidnas. The platypus is distinctive for its duck-bill and webbed feet and is one of the very few mammals that lay eggs.