Which one of the following is different from the others?

$S$ - Statement: Kangaroo is a mammal.
$R$ - Reason: The diaphragm is present in the body cavity.

Which of the following characteristics is associated with the life of mammals?

Which of the following animals possesses oval-shaped $RBCs$?

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 characteristic is found exclusively in mammals?