I WONDER - Are There Any Mammals That Lay Eggs?

Mammals are distinct from other animals as they give birth to live young, unlike reptiles and birds that lay eggs. However, the duck-billed platypus and the ancheta are exceptions, as they lay eggs despite being mammals. This rare trait is believed to be due to their ancestors' adaptation to aquatic life, even though they are primarily land animals.

How do the reproductive methods of mammals differ from those of reptiles and birds?

What is the significance of the duck-billed platypus in the study of mammalian reproduction?