Which animal performs respiration but does not possess a specialized respiratory organ?

In crustaceans,respiration takes place by

Among vertebrates,...$A$... use gills whereas reptiles,birds and mammals respire through the ...$B$... Amphibians like frogs can respire through ...$C$... also. Mammals have a well adapted respiratory system. Select appropriate choice for the blanks $A, B$ and $C$ to complete the given $NCERT$ statement.

Skin is an accessory organ of respiration in

Given below are four matchings of an animal and its kind of respiratory organ:
$I.$ Silver fish - Trachea
$II.$ Scorpion - Book lung
$III.$ Sea squirt - Pharyngeal gills
$IV.$ Dolphin - Skin
The correct matchings are:

Which of the following is not a character of a respiratory surface?