A nematocyst is the stinging capsule within a cnidocyte. Its rapid discharge helps immobilize prey and is one of the diagnostic features of phylum Cnidaria. This MCQ belongs to the Cnidaria topic in Animal Diversity-I and is written to test concept understanding rather than memorized wording.
Planaria is a common free-living turbellarian flatworm. It is famous for regeneration and is often used to study basic flatworm structure and acoelomate organization. This MCQ belongs to the Turbellaria topic in Animal Diversity-I and is written to test concept understanding rather than memorized wording.
Ecdysis is molting of the outer cuticle. Nematodes and arthropods both molt, which is one reason they are grouped among ecdysozoan animals in modern phylogeny. This MCQ belongs to the Nematoda topic in Animal Diversity-I and is written to test concept understanding rather than memorized wording.
The mantle cavity is the space between mantle and visceral mass. It often houses gills and receives openings of digestive, excretory, and reproductive systems. This MCQ belongs to the Mollusca topic in Animal Diversity-I and is written to test concept understanding rather than memorized wording.
Correct Answer: A. protoplasmic level of organization
Explanation:
Protozoans show a protoplasmic level of organization because one cell performs all vital life functions. They do not possess true tissues or organs, although organelles may be specialized for particular activities. This MCQ belongs to the Protozoa topic in Animal Diversity-I and is written to test concept understanding rather than memorized wording.
Phylogenetic relationships are best inferred from shared derived characters, also called synapomorphies. These traits appear in a common ancestor and are inherited by its descendants, so they are more useful than superficial similarities such as size, colour, or habitat. This MCQ belongs to the Taxonomy topic in Animal Diversity-I and is written to test concept understanding rather than memorized wording.
Amoeba moves and feeds by pseudopodia, which are temporary extensions of cytoplasm. These projections help in amoeboid locomotion and engulfing food particles by phagocytosis. This MCQ belongs to the Amoeba topic in Animal Diversity-I and is written to test concept understanding rather than memorized wording.
Species is the basic and most specific unit used in biological classification. Higher ranks such as genus, family, order, class, and phylum group organisms more broadly and contain multiple species. This MCQ belongs to the Taxonomy topic in Animal Diversity-I and is written to test concept understanding rather than memorized wording.
Paramecium uses cilia for locomotion and feeding currents. Cilia beat in coordinated waves and are shorter and more numerous than flagella. This MCQ belongs to the Paramecium topic in Animal Diversity-I and is written to test concept understanding rather than memorized wording.
Radial symmetry allows the body to be divided into similar halves along more than one plane through the central axis. It is common in many sessile or slow-moving aquatic animals such as cnidarians. This MCQ belongs to the Animal architecture topic in Animal Diversity-I and is written to test concept understanding rather than memorized wording.
Euglena moves mainly by a flagellum. It is often studied as an animal-like protist because it can move actively, but it also contains chloroplasts and can photosynthesize. This MCQ belongs to the Euglena topic in Animal Diversity-I and is written to test concept understanding rather than memorized wording.
Bilateral symmetry is associated with active directional movement and cephalization. It produces right and left halves and often allows development of a head region containing sensory structures. This MCQ belongs to the Animal architecture topic in Animal Diversity-I and is written to test concept understanding rather than memorized wording.
