Which of the following is the largest mammal?

Assertion : The duck-billed Platypus and the spiny ant-eater,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.

Assertion $(P)$: Mammals are viviparous.
Reason $(Q)$: Mammals possess external pinnae.

Which two additional cranial nerves are present in mammals compared to lower vertebrates?

Which pair of characters are found without exception in all mammals?

Bats are included in the same taxonomic class as.....