Zoology MCQs for NEET — Practice Questions with Answers

The cavity in coelenterates (cnidarians) is called the coelenteron. It is a single internal cavity that serves both digestive and circulatory functions. Hence, the correct option is o1: coelenteron.

Sea anemones belong to the phylum Coelenterata, also known as Cnidaria. This phylum includes aquatic animals like jellyfish, corals, and hydras, which possess specialized cells called cnidocytes for capturing prey. Protozoa are single-celled organisms, Porifera includes sponges, and Echinodermata includes starfish and sea urchins, which are not related to sea anemones.

Nephridia in earthworms are excretory organs that perform a similar function to the flame cells in planaria. Both structures help in the removal of metabolic waste from the body. Gills in prawns are used for respiration, trachea in insects are for gas exchange, and nematoblasts in Hydra are involved in defense and prey capture, not excretion.

Taenia solium, commonly known as the pork tapeworm, belongs to the phylum Platyhelminthes. This phylum comprises flatworms, which are characterized by their flattened bodies. Aschelminthes includes roundworms, Annelids include segmented worms like earthworms, and Mollusca includes snails and octopuses.

Ascaris, a parasitic roundworm, is commonly found in the alimentary canal of its host. Specifically, it resides in the small intestine where it feeds on the host's digested food. This is a key point for NEET students to remember as it highlights the parasite's habitat and its impact on the host's digestive system.

In Pheretima (earthworm), locomotion occurs with the help of circular muscles, longitudinal muscles, and setae. The coordinated contraction and relaxation of these muscles, along with the anchoring action of the setae, enable the earthworm to move through soil. Understanding this mechanism is crucial as it demonstrates the complex interaction of different muscular and structural components in annelid locomotion.

A body cavity lined by mesoderm is called a coelom. This is a true body cavity found in coelomate animals, which allows for the development of complex structures and organ systems. NEET students should note the distinction between coelomates and other types of body plans, such as pseudocoelomates and acoelomates, for a comprehensive understanding of animal anatomy.

Prawns are crustaceans, which are a large, diverse group of arthropods that also include crabs, lobsters, and shrimp. Crustaceans typically have a hard exoskeleton and jointed limbs.

The excretory organs in cockroaches are Malpighian tubules. These tubules are responsible for the removal of waste products from the hemolymph (insect blood) and help in osmoregulation.

Animals that are active during the night are called 'nocturnal'. They have adapted to low light conditions and often have enhanced senses like improved vision or hearing to navigate and hunt in the dark. Examples include owls, bats, and many rodents.