Multiple choice general knowledge science & technology Which of the following mammals that lay eggs? Platypus Echidna None of them Both of them Reveal answer Fill a bubble to check yourself D Correct answer Explanation Monotremes are a group of egg-laying mammals. Both the platypus and echidna (spiny anteater) are monotremes found in Australia and New Guinea. They are the only mammals that lay eggs instead of giving live birth.