Free Kingdom Animalia MCQs with Answers

651. Direct ancestors of grade radiata are:

• A. Parazoa
• B. Porifera
• C. Protozoa
• D. Eumetazoa

Explanation: The correct answer is Eumetazoa. Eumetazoa encompasses animals with true tissues and organized body structures, which aligns with the characteristics of grade Radiata, featuring animals with radial symmetry like cnidarians and ctenophores. In contrast, Parazoa and Porifera lack true tissues, preventing them from being direct ancestors of Radiata. Protozoa, being single-celled organisms under Protista, are even further removed from the multicellular and tissue-based ancestry of Radiata.

652. The excretory system in Platyhelminthes is in the form of:

• A. Flame cells
• B. Metanephridium
• C. Malpighian tubules
• D. Kidneys

Explanation: Flame cells, also known as protonephridia, are the excretory structures found in Platyhelminthes. These cells have a tubule with a ciliated structure that resembles a flame. They help regulate osmotic balance and remove waste products.

653. Ascaris is the endoparasite of:

• A. Small intestine
• B. Large intestine
• C. Rectum
• D. Appendix

Explanation: Ascaris is an endoparasitic roundworm that primarily resides in the small intestine of its host. It is known as an intestinal parasite.

654. Which of the following characters do not belong to Birds?

• A. Presence of feathers
• B. Presence of gills
• C. Beak
• D. Sternum

Explanation: Gills are not present in birds.Birds are terrestrial and aerial vertebrates that breathe through lungs, not gills. Gills are respiratory organs found in aquatic animals like fishes and amphibian larvae. Since birds lack gills, this feature does not belong to birds, making this the correct answer.

655. Frogs differ from humans in possessing:

• A. Paired cerebral Hemispheres
• B. Nucleated red blood cells
• C. Hepatic portal system
• D. Presence of endocrine tissues

Explanation: Frogs have nucleated red blood cells (RBCs), whereas humans have non-nucleated RBCs. Nucleated RBCs are a characteristic feature in many non-mammalian vertebrates, including amphibians like frogs.

656. The animals without a body cavity belongs to:

• A. Eumetazoa
• B. Coelomata
• C. Pseudocoelomata
• D. Acoelomata

Explanation: Acoelomates are animals that lack a true body cavity called a coelom. Unlike animals with a coelom (coelomates) or a pseudocoelom (pseudocoelomates), acoelomates do not have a fluid-filled body cavity between the gut and body wall. Flatworms (phylum Platyhelminthes) are examples of acoelomates.

657. Pseudocoelom is characteristics feature of:

• A. Aschelminthes (Nematoda)
• B. Mollusca
• C. Annelida
• D. Porifera

Explanation: Aschelminthes, also known as Nematoda, is a phylum of invertebrates that includes roundworms. These organisms are characterized by their cylindrical, unsegmented body and a pseudocoelom, which is a fluid-filled body cavity that is not fully lined with mesoderm. The term "pseudocoelomates" refers to animals that have a pseudocoelom.

658. Pseudocoelom is present in:

• A. Cnidaria
• B. Round worms
• C. Flat worms
• D. Earth worms

Explanation: Nematodes belong to the phylum Nematoda, and they are characterized by having a pseudocoelom, which is a fluid-filled body cavity that is not completely lined with mesoderm. The pseudocoelom in nematodes serves various functions, including providing a hydrostatic skeleton for support and facilitating the movement of nutrients and waste products within the body.

659. Polymorphism is a characteristic of members of phylum:

• A. Porifera
• B. Annelida
• C. Cnidaria
• D. Arthropoda

Explanation: Polymorphism is a characteristic found in members of the phylum Cnidaria. Cnidaria is a diverse group of aquatic invertebrates that includes jellyfish, corals, sea anemones, and hydroids. One of the defining features of cnidarians is their possession of specialized stinging cells called cnidocytes, which contain nematocysts used for capturing prey and defense. Polymorphism in cnidarians refers to the existence of different body forms within a single species. Many cnidarians exhibit two or more distinct morphological forms, each specialized for different functions or stages of their life cycle.

660. Hydra belongs to phylum:

• A. Mollusca
• B. Annelida
• C. Cnidaria
• D. Arthropoda

Explanation: Hydra is a genus of small, freshwater organisms belonging to the phylum Cnidaria. Cnidaria includes a diverse group of aquatic invertebrates that also comprises jellyfish, corals, sea anemones, and hydroids.Hydra are simple, predatory animals with a tubular body and a basal disc that allows them to attach to surfaces in freshwater habitats, such as ponds, lakes, and slow-moving streams. They possess specialized stinging cells called cnidocytes, which are found in their tentacles and are used for capturing and immobilizing prey.