Which of the following is absent in a $Salamander$?

$Assertion (S)$: In amphibians,the skin is thin,moist,and highly vascularized.
$Reason (R)$: Amphibians perform cutaneous respiration through their skin.

Iodine deficiency in frog tadpole will lead to

Which class of animals lives in both water and on land?

$A$: Dicondylic skull is found in amphibians and mammals.
$R$: The number of cranial nerves in amphibians and mammals is same.

Which statement is wrong about $Amphibia$?