Unemployment has been falling steadily since December 1992. The proportion of people of working age who actively seek work is tending to increase, so if unemployment is not to rise, the number of jobs available has to increase. Over the past ten years, the UK economy has continued to grow, new jobs have been created, and the number of people with a job is currently at a record high. This is a significant achievement and a major contributor to citizens' welfare. Some problems remain, however:

11. What type of circulatory system is present in annelids?

12. Does annelid blood contain a respiratory pigment?

13. How can the presence, location and function of muscle tissue in organisms of the phylum Annelida be explained?

14. How can the excretory system of annelids be described?

15. How can the nervous system in organisms of the phylum Annelida be described? How can the cephalization in annelids be compared to cephalization in nematodes and platyhelminthes?

16. What is the clitellum of earthworms and where it is located?

17. In terms of the occurrence of separate sexes, how can organisms of the phylum Annelida classified?

18. Is embryonic development in earthworms direct or indirect?

19. What is the name of the larval stage of polychaetes?

20. Into which classes is the phylum Annelida divided?