In which of the following is premature birth observed?

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 $Oryctolagus$?

$A$ group of animals having a marsupium is

Which of the following groups of animals are generally viviparous?

Which of the following is not a mammalian character?

Which of the following is $NOT$ true for an elephant?