Free Kingdom Animalia MCQs with Answers

231. Free swiming larvae are produced during the lifetimes of:

• A. Coelenterate
• B. Annelida
• C. Porifera
• D. Arthropods

Explanation: Free-swimming larvae are produced during the lifetimes of some annelids, particularly in the class Polychaeta. Annelids are segmented worms, and the class Polychaeta is the largest and most diverse group within the phylum Annelida.In many polychaete species, the life cycle includes a larval stage known as the trochophore larva. The trochophore larva is a free-swimming, planktonic larval form that hatches from fertilized eggs. It is typically ciliated and has a ring of cilia around its body, which it uses for locomotion and feeding. The cilia create a characteristic rotating band, resembling a "trochus," hence the name "trochophore."

232. A blue colored respiratory pigment called hemocynanin is found in:

• A. Molluscs
• B. Annelids
• C. Athropods
• D. Echinoderms

Explanation: A blue-colored respiratory pigment called hemocyanin is found in mollusks. Hemocyanin is a copper-based oxygen-carrying protein that plays a vital role in oxygen transport within the circulatory system of many mollusks. In most vertebrates, oxygen is transported by the iron-containing protein hemoglobin found in red blood cells. However, in some invertebrates, including certain mollusks, the oxygen transport is achieved by hemocyanin. Hemocyanin is found dissolved directly in the blood plasma, rather than within specialized cells like hemoglobin. When mollusks are exposed to oxygen, hemocyanin binds with the oxygen molecules, forming a blue-colored complex. This oxygenated form of hemocyanin is responsible for transporting oxygen from the gills (or other respiratory structures) to various tissues throughout the body.

233. Aquatic arthropods respire through:

• A. Lungs
• B. Gills
• C. Skins
• D. Spiracles

Explanation: Aquatic arthropods respire through gills. Gills are specialized respiratory organs that allow these arthropods, such as crustaceans (e.g., crabs, lobsters, shrimp) and some insects (e.g., aquatic beetles), to extract dissolved oxygen from water and release carbon dioxide.Gills are typically thin and highly vascularized structures that provide a large surface area for efficient gas exchange. As water flows over the gills, oxygen diffuses from the water into the blood vessels in the gills, while carbon dioxide from the blood diffuses into the water and is released.

234. A rasping tongue like radula having horny teeth is present in:

• A. Sponges
• B. Annelids
• C. Coelontorates
• D. Molluscs

Explanation: A rasping tongue-like radula with horny teeth is present in mollusks, particularly in the classes Gastropoda (snails and slugs) and Polyplacophora (chitons). The radula is a specialized feeding organ found in many mollusks, and it serves as a unique adaptation for grazing and consuming a variety of food sources. The radula is located within the mouth of the mollusk and consists of rows of tiny, chitinous teeth that are used for scraping and rasping food particles from surfaces.

235. The animals in which body can be divided into to equal halves in one plane only, are called:

• A. Eumatozoa
• B. Radial
• C. Bilateral
• D. Parazoa

Explanation: Their bodies have distinct right and left halves that are mirror images of each other. Bilateral symmetry allows for more directed movement and a clear front (anterior) and back (posterior) orientation. This body plan is more complex and represents a significant evolutionary advancement over radial symmetry.

236. It is universally accepted by biologists that mammals have evolved from reptilian ancestors called _

• A. Cotylosaurs
• B. Cyclostomata
• C. Dinosaurs
• D. Amphibians

Explanation: It is universally accepted by biologists that mammals have evolved from reptilian ancestors called Cotylosaurus.

237. The largest invertebrate animal is

• A. Octopus
• B. Andonta
• C. Squid
• D. Oyster

Explanation: Factual recall. The largest invertebrate animal is the Giant Squid belonging to Class Cephalopoda of Phylum Mollusca.

238. The cartilaginous fishes contain scales:

• A. Placoid
• B. Ganoid
• C. Cycloid
• D. Ctenoid

Explanation: Placoid scales (microscopic) are a characteristic of Chondricthyes also known as Elasmobrachi. While Ganoid, Cycloid and Ctenoid scales are found in Osteichthyes also known as Teleostomi.

239. An outer flexible cover of tunicates is _

• A. Tunic
• B. Cell wall
• C. Cuticle
• D. Pellicle

Explanation: The bodies of Urochordates also known as sea tunicates or sea squirts is covered with a sac like tunic made of leathery material called tunicin.

240. Marsupium is a characterstic feature of _

• A. Opossum
• B. Dolphin
• C. Echidna
• D. Duckbill platypus

Explanation: Marsupium is a characteristic feature of the sub-class metatheria under class mammalia. Examples of marsupials include: Opossum, Kangroo, Tasmanian Wolf.