Question

Wuchereria bancrofti belong to the phylum
A. Nemathelminthes
B. Platyhelminthes
C. Nematoda
D. Coelenterate

Answer 1

Hint: A Wuchereria bancrofti species belong to the family called Onchocercidae. They are the human parasitic worms which infect the lymphatic system and cause the lymphatic filariasis. These organisms inhabit a broad range of environments.

Complete answer:
We all are familiar with the earthworms, mostly found in garden soil. Many different types of animals are commonly called “worms”; there are many distinct phyla that fit the category. They (worms) are long and thin organisms that get around efficiently without legs. The various phyla of worms display vary in size, body structure and complexity. The phylum Platyhelminthes includes the flatworms, they are simple animals. They are slightly more complex as compared to the cnidarians. Roundworms fall under the phylum called Nematoda, they have a complex body structure. Phylum Annelida have segmented worms that have more complex body plans.
The roundworms or nematodes are together establishing the phylum Nematoda or Nemathelminthes. The plant-parasitic nematodes are called eelworm. They may be found as aquatic, terrestrial, as free-living or parasitic in animals and plants. They have an organ-system level of body organisation. The alimentary canal is complete and has developed muscular pharynx. They excrete out body waste with the help of the excretory tube from the body cavity through excretory pores. They have distinct male and female worms; therefore, they are called dioecious organisms. They have internal fertilisation and development can be direct or indirect.
Examples: Ancylostoma (Hookworm), Ascaris (Roundworm), Wuchereria (Filarial worm)

Hence, the correct option is A (Nemathelminthes).

Note: Wuchereria infect the lymphatic system via insects as a vector. The lymphatic filariasis is caused by any of these three species, W.malayi, Brugia timori and W.bancrofti. W.bancrofti is most commonly found in Central America and South America, Central Africa etc.