What are the importance of leeches?

How much does a ladybug weigh in tons? What does a dead bee symbolize? When earthworms add their wastes to the soil then die and decay this contributes to? Where does phylum annelida get its name? Do breadcrumb sponges have spicules? Do sandworm have coelom? What is in the tubli roots that can be used to make insecticides? Is a moose a herbivore or a carnivore or an omnivore or insectivore? Bugs with odor? What do you call the black liquid that squids squirt? What will you look for to identify the sex of the female cockroach? What is a Sawyer extractor kit? Is a worm a composer? Are Asian tiger mosquitos dangerous? How did they get rid of lice in world war 1? Do tarantulas have eight legs? What is the problem of keeping crayfish as a pet? What are the adaptations for a rhino beetle? What causes jellyfish to come onshore? Will a plant with water and no sunlight survive longer than a plant with sun and no water?