Free Biodiversity and Variety of Life MCQs with Answers

1371. Which group of organisms has the following features?1. Three pairs of jointed legs2. Three-part segmented body3. One pair of antennae

• A. Arachnoids
• B. Crustaceans
• C. Insects
• D. Myriapods

Explanation: In insects, the head bears a pair of antennae, which serve as important sensory organs for detecting smell, touch, and vibrations, and also carries compound eyes, each made up of many small visual units that provide a wide field of view. The insect body is divided into three distinct regions: head, thorax, and abdomen. The thorax, which is the locomotory center, consists of three segments prothorax, mesothorax, and metathorax. Each of these segments carries one pair of jointed legs, giving insects a total of three pairs of legs. Additionally, many insects bear one or two pairs of wings on the middle and last thoracic segments, making them the only invertebrates capable of active flight. The abdomen contains major internal organs, including those for digestion, excretion, and reproduction, completing the characteristic body plan of insects.

1372. The lower jaw is composed of only one large bone:

• A. Reptiles
• B. Amphibian
• C. Chondrichthyes
• D. Mammals

Explanation: The lower Jaw of mammals consists of only one bone, the dentary, and the jaw hinge connects the dentary to the squamosal (flat) part of the temporal bone in the skull. Working together, these muscles permit up-and-down and side-to-side movements of the jaw,making chewing possible which is unique to mammals.

1373. 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.

1374. 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.

1375. 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.

1376. 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.

1377. 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.

1378. 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.

1379. 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.

1380. 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.