Which one of the following is a metatherian mammal?

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 $Oryctolagus$?

Which of the following is a unique characteristic of mammals?

Define Homeothermy and Poikilothermy.

Which of the following is an oviparous mammal?

Select the odd one out.