Which one of the following is an exclusive character of class Mammalia?

Note the following:
$I.$ Dentition is heterodont.
$II.$ Canines are poorly developed.
$III.$ Incisors are chisel-like,poorly developed.
$IV.$ Herbivorous and diastema is present.
$V.$ The dental formula is $I \frac{2}{1}, C \frac{0}{0}, P m \frac{3}{2}, M \frac{3}{3}$.
Which of the above are true for $Oryctolagus$?

The order $Insectivora$ comes under:

Which of the following mammals have a cloaca?

The renal portal system is absent in which of the following?

The feet with two toes forming a cloven hoof are seen in: