Which of the following is not found in the skin of a frog?

Which of the following is $NOT$ a function of the skin of a frog?

Which of the following structures is found only in the male frog?

Frog can protect itself from enemies by?

Which of the following structures is not present in a female frog?

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: