Question

Which type of respiratory organs are present in spiders and scorpions?
A. Book lungs
B. Gill books
C. Gills
D. Lungs

Answer 1

Spider and scorpion are classified under the Arachnid class. Arachnid is a joint-legged invertebrate animal having legs, the front pair of the leg in some species have been converted to sensory function. This arachnid class of species exchanges the atmospheric gases through a stalk of alternating air pockets and tissue filled with hemolymph giving the appearance of a folded book.

Complete answer:
Both the creature's spider and scorpion along with the mite, ticks, and harvestman are classified under the Arachnid class and subphylum Chelicerata. This joint-legged invertebrate possessed $8$ Legg, however, the $2$ pairs of appendages are for feeding, defense, and sensory function. Scorpion and spider use book lung for the atmospheric gaseous exchange. It is a special type of respiratory organ present in all arachnids.
Each of these organs is located inside an open ventral abdominal, air cavity connects with the surrounding through an opening for respiration. Alternating air pockets are arranged in stalks and tissue filled in hemolymph giving the appearance of a folded book, so it is called a Book lung. These plates of folded books maximize and facilitate the exchange of air from the atmosphere. There are $4$ pairs in scorpions and $2$ in spiders.
Book gills are similar to book lungs. It is believed that book lungs are evolved from book gills but book gills are external whether book lungs are internal. Book gills are still present in some marine arthropods to facilitate respiration.
Gills are the respiratory organs present in aquatic organisms that extract dissolved oxygen from water and excrete carbon dioxide.
Lungs are the respiratory organs present in mammals. These are present in pairs located on either side of the thorax cavity.
So, the correct answer is “Option A”.

Note:
Book lungs are the respiratory organs present in scorpion and spider. Each book lung is arranged in the alternate stalk of the series giving the appearance of a folded book. Each page or plate is highly vascular. These plates extend into an internal pouch formed by the skeleton that opens to the exterior slit. These provide an exchange of gases with the surrounding atmosphere.