The heart is $3$ or $4$ chambered in the vertebrate group:

Carapace is present in

$A$: The tortoise is classified under the class $Reptilia$.
$R$: The tortoise is a triploblastic,poikilothermic animal with epidermal scales.

The reptile which glides in the air is

Which of the following snakes has hind legs?

Given below are two statements:
Statement $I$: The class name Reptilia refers to creeping or crawling mode of locomotion.
Statement $II$: All organisms belonging to Reptilia have three chambered heart.
In the light of the above statements, choose the most appropriate answer from the options given below: