Question

Directions: Choose the term or expression which best answers the question or completes the statement. 7. The most posterior component of an annelid is referred to as a. the pygidium b. the prostomium c. the trunk d. the parapodea e. choices a and b 8. In the annelid, the production of new body segments is referred to as a. homoblastic growth b. heteroblastic growth c. teloblastic growth growth e. no choice is correct f. both cand d are correct. d. meroblastic 9. In general, polychetes locomote by a. changes in hydrostatic pressure b. muscle contraction c. movement by uripodea d. choices a, b, c e. choices a and b 10. Mandibles are present in the a) oligochetes b. clitellates c. polychetes d, Hirudinea e. girdle worms 11. Which of the following annelids affect sediment fertility? a. polychetes b. oligochetes c. the Hirudinae d. all choices are correct e choices a and b f. no choice is correct.

Answer 1

7. Answer:- option a is correct. Explanation- Phylum annelids body plan has 3 parts- a) prostomium-anterior part, b) segmented body- followed by prostomium, and 3) pygidium- posterior terminal portion

8. Answer:- option a is correct. Annelids exhibit spiral homoblastic growth of metamerism. Body is divided into linear series of similar segments, which are separated from one another externally by inter segmented grooves and internally by inter segmental septa.

9. Answer:- option d is correct. Polychetes locomote with the help of longitudinal muscles, hydrostatic pressure produced by coelomic fluid and a special locomotory organs called parapodia(uripodia). longitudinal muscles and coelomic fluid are commonly used for locomotion in all annelids including polychetes. Parapodia are lateral extentions of the body wall that help in locomotion in this group of annelids.

10. Answer:- option c is correct. Few marine polychetes predators have Mandible(jaws) with teeth made up of chitin. This is an exceptional feature of annelids.

11. answer:- option e is correct. Both polychetes and oligochetes have important role in turning sediment in aqatic habitat by borrowing. Turning sediment enriches it with organic contents. Thus they affect sediment fertility.