1- what size are nematodes?
2- where is the copulatory organ of a male spider?
3- what is a common name for nematodes?
4- how many species of nematodes have been described?how many are estimated to exist?
5- how does the external covering of nematodes differ from arthropods?
6- what is the economic importance of nematodes?
7- which nematodes is a "genetic model organism"?
8- what do "arthro" and "pod" mean?
9- what are the four major arthropod phyla living today? which one contains the insects,and which the spider,and which the centipedes?