Question

Which of the following is not a typical character of phylum nematodes.
A. Syncytial epidermis
B. Pseudocoel
C. Nonliving cuticle
D. Gaseous exchange through gills

Answer 1

Hint: Phylum nematoda also called the Phylum of non segmented roundworms. Phylum nematoda is also known as aschelminthes. The body of the aschelminthes is circular in cross-section hence the name roundworms. They belong to the animal kingdom which are characterized by the absence of a cell wall in their cell.

Complete Answer:
- Animals in phylum nematoda are free living, aquatic and terrestrial or parasitic in plants and animals. Roundworms have an organ system level of body organisation.
- They are bilaterally symmetrical, triploblastic and Pseudocoelomates animals. Alimentary canal is complete with a well developed muscular pharynx.
- Their cuticles are non living. They have syncytial epidermis. Gaseous exchange occurs through the body surface.
- An excretory tube removes body waste from the body cavity through the excretory pore. Sexes are separate that means they are dioecious males and females are distinct. Often females are longer than males.
- Fertilization is internal and development may be direct (the young ones resemble the adult) or indirect.

So the correct answer is (D).

Note: In spite of differences in Structure and in form of different Animals. There are fundamental features common to various individuals in relation to the arrangement of cells, body symmetry, nature of coelom, patterns of digestive, circulatory or reproductive system. These features are used as the basis of animal classification and some of them are level of organisation, body symmetry, Diploblastic and Triploblastic organisation and segmentation of the body of organisms.