What is the genus of the frog?

The sensory papillae in frogs are associated with

The Indian bullfrog is $..........$.

The forelimbs and hindlimbs of a frog have how many digits respectively?

Male frogs can be distinguished from female frogs due to the presence of:
$A$. Bulging eyes
$B$. Vocal sacs
$C$. Webbed digits in feet
$D$. Copulatory pad on first digit of fore limbs
$E$. Olive green-coloured skin with dark irregular spots
Choose the correct answer from the options given below:

Why is the frog considered suitable for classroom studies?