In which of the following are book lungs found?

Explanation

Book lungs are respiratory organs found in certain arthropods, specifically spiders and some related arachnids. They are not present in the other organisms listed. Clams are bivalve mollusks, and their respiratory system primarily consists of gills. They have specialized structures called ctenidia or gill filaments that extract oxygen from water. Spiders possess book lungs, which are unique to this group of arachnids. Book lungs are located in the abdomen and are used for respiration. They consist of a series of thin, membranous plates arranged like the pages of a book, which are richly supplied with blood vessels. Oxygen exchange occurs across these thin plates. Silverfish, also known as Lepisma, are wingless insects. Unlike spiders, they do not possess book lungs. Silverfish respire through small openings called spiracles found on the sides of their body. These spiracles connect to a network of tubes called tracheae, which distribute oxygen directly to their cells. Leeches are annelids, which are segmented worms. They do not possess book lungs. Leeches are aquatic or terrestrial organisms and respire through their skin. Oxygen diffuses through their moist body surface into their circulatory system, allowing respiration to occur.In summary, book lungs are found in spiders (option 2), whereas clams (option 1), silverfish (option 3), and leeches (option 4) employ different respiratory mechanisms.