Assertion : The duck-billed Platypus and the spiny ant-e ater, both are egg-laying animals yet they are grouped under mammals. Reason : Both of them have seven cervical vertebrae and 12 pairs of cranial nerves.

Step-by-step solution

To be a mammal the presence of hair and milk or mammary gland is must, but presence of 7 cervical vertebrae and 12 pairs of cranial nerves are also additional mammalian characteristics. The monotremes make up by far the smallest subclass of mammals, with just three species, found in Australia, Tasmania, and New Guinea. One of these is the duck-billed platypus, and the remaining two are the echidnas, or spiny anteaters.The duck-billed platypus and the spiny anteater are mammals that lay eggs rather than give live bi