Question

Liver fluke belongs to class
A. Trematoda
B. Turbellaria
C. Cestode
D. Nematoda

Answer 1

Hint: Liver flukes are parasitic animals that belong to phylum Platyhelminthes. They are triploblastic dorsoventrally flattened acoelomate animals without a definite anus. The animals of this phylum can be free living or parasitic.

Complete answer:
Trematoda is a class under phylum Platyhelminthes. This class generally contains flukes like Liver Flukes. They are worms like small animals with a flattened body. The trematodes are hermaphrodites with a pair of testes and one ovary. The life cycle of these animals is completed in two hosts – the definitive host and the intermediate host. The sexual reproduction is completed in the definitive host while the intermediate host hosts the asexual reproduction. The intermediate host for Liver Fluke is mollusks like snails and their definitive host is cattle or sheep.
Turbellaria is the class under phylum Platyhelminthes which comprises organisms that are not exclusively parasitic. Their body is not covered with any cuticle but with a single layer of cells. Each of these cells have multiple cilia. The cilia are generally used for locomotion. Organisms of this class generally reproduce by budding or cloning. However, they are also capable of sexual reproduction, since they are hermaphrodite animals. Copulation is internal in these species.
Cestoda is a class under phylum Platyhelminthes which comprises parasitic worms. The most widely known representative of this class is the Tapeworm. The cestodes complete their life cycle in a definitive vertebrate host and one or two intermediate hosts. Humans are infected with tapeworms if they consume undercooked pork or beef. Examples of cestodes are Taenia solium, Taenia saginata, etc.
Nematoda is a phylum under invertebrates. This phylum mainly comprises roundworms. Some of the animals of this phylum are free living and others parasitic. A few species exhibit self-fertilization and majority are dioecious animals, that is male and females are separate. These animals can cause diseases like ascariasis, filariasis in human beings. Common species of this phylum are Caenorhabditis elegans, Ascaris species, Trichinella species.

Therefore, option (A) is correct.

Additional Information: Boron is an important micronutrient in plants. It helps to maintain the integrity of the plant cell walls and regulate certain metabolic pathways in plants. Boron is present in water soluble and insoluble forms in plants. It is the lack of water-soluble boron that accounts for boron deficiency. The optimum boron content is about 20-100ppm. Excessive boron concentration can lead to toxicity in plants.

Note: Liver flukes are parasites that belong to phylum Platyhelminthes. They exhibit a leaf-like body covered with tegument. These parasites are known to complete their life cycle in two hosts. They are hermaphrodites, that is a single worm containing both male and female reproductive organs. Liver flukes are known to cause Fasciolosis in sheep and cattle. In human beings they have the potency to cause jaundice, anemia, swollen liver.