Q. Consider the following animals:
  1. Platypus
  2. Echidna
  3. Armadillo
  4. Pangolin
Which of the above are egg-laying mammals?

Answer: Only 1 and 2
Notes: Among the animals listed, only the Platypus and the Echidna are monotremes, a group of egg-laying mammals. Armadillos and Pangolins are mammals as well, but they give birth to live young and do not lay eggs. Thus, only options 1 and 2 are correct.