How many hearts does an earthworm have?
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An earthworm has 5 hearts, and it has a closed circulatory system, in which blood is confined to vessels.
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It is called regeneration. Worms can do it because they have more than one heart. If you separate the worm a part with a heart in it will keep living.\n\n-Trey
935334
You friend is wrong. Some worms continue to live as two worms if you cut them up, or the living part grows again.\n\nBut if you cut up a snake, you break its backbone. No creature survives a cut up back bone. Yes, it dies.
1178036
the excretory organs of earthworm
650989
The puzzle is looking for a word for worm.  I think it is probably Platyhelminthes.  This is 15 letters, so maybe the puzzle should say 15 instead of 13.  Maybe there is some other type of worm that they are looking for.  Other possibilities include Chaetognatha (12 letters)
539819
There is lots of factors limiting where worms can live.  For example: food availability, water availability, oxygen availability, compaction, temperature (frozen soil or boiling hot soil), etc
532264
Yes, there is a kind of black earthworm. Fish likes them better than normal ones, so some of the experienced fishermen prefer to use this kind of earthworms. But these worms smells very bad.
191693
Yes, a worm, a squid, and also an octopus all have three hearts.
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in what kind of organism???\n\nit must be a lot for polychaeta, about 2 or 3 pairs in each segments.\n1pair  for oligochaeta
362865
earthworms, which generally live in the soil are unable to properly respire when the soil becomes too concentrated with water.  since water has 1/10 the amount of oxygen that air has, the worms must come to the surface, which in your case, is the concrete parking lot.  they are able to locomote by peristalsis (muscle movements that run around their bodies and well as longitudinally)
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Duma, I see you've already asked this question twice. What you should do is contact some invertebrate researcher (in a museum or natural history institution) for help, because local keys and checklists of fauna are not easy to find unless one knows where to look for them.\n\nHere are some links to papers with reference to Asian species, that's the closest I could get.\nhttp://zoolstud.sinica.edu.tw/Journals/39.4/285-294.pdf\nhttp://zoolstud.sinica.edu.tw/Journals/40.4/276.pdf\nhttp://www.senckenberg.uni-frankfurt.de/odes/03-11.pdf\n\nHere's a link to a journal that specializes in invertebrate systematics:\nhttp://www.publish.csiro.au/nid/121/issue/529.htm\n\nAnd here's the citation of two papers about freshwater earthworms:\n \nOhtaka, A.; Usman, R. 1997. Records of tubificid oligochaetes from Padang, West Sumatra, Indonesia, with description of a new species of Aulodrilus Bretscher. Species Diversity 2: 145-154.\nOhtaka, A.; Hartoto, D.I.; Usman, R. 2000. Preliminary study on freshwater Oligochaeta in Indonesia. Rep. Suwa Hydrobiol. 12: 29-38\n\nYou coult try to contact Mr Ohtaka.\nhttp://read.jst.go.jp/ddbs/plsql/KNKY_EG_24?code=1000003153
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Earthworms travel underground by the means of waves of muscular contractions which alternately shorten and lengthen the body. The shortened part is anchored to the surrounding soil by tiny claw-like bristles (setae) set along its segmented length. (Typically, earthworms have four pairs of setae for each segment but some genera are perichaetine, having a large number of setae on each segment.) The whole process is aided by the secretion of a slimy lubricating mucus
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Only one - they are hind gut fermenters like species such as horses and rabbits, as opposed to ruminants which have different chambers of the stomach opening and ferment their food there.  They do have a large caecum (closest human equivilant would probably be the appendix, I believe) to help them do this.
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One.\n\nPraying Mantis' have two, one in the head and one in their tail.\n\nHomework question?
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humans (mammals) have 4 chambered hearts and frogs (amphibians) have three chambered hearts.\nin humans, half the heart sends oxygen poor blood to the lungs and the other half sends oxygen rich blood to the body. each half has its own atrium that collects blood, and ventricle that pumps it.\nin frogs, there are seperate atriums but 1 ventricle that pumps both at the same time, so the low oxygen and high oxygen blood mix a little bit.
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http://en.wikipedia.org/wiki/Parelaphostrongylus_tenuis\n\nMorphology\n\nRoundworms are triploblastic protostomes with a complete digestive system. Roundworms have no circulatory or respiratory systems so they use diffusion to breathe and for circulation of substances around their body. They are thin and are round in cross section, though they are actually bilaterally symmetric. Nematodes are one of the simplest animal groups to have a complete digestive system, with a separate orifice for food intake and waste excretion, a pattern followed by all subsequent, more complex animals. The body cavity is a pseudocoel (persistent blastula), which lacks the muscles of coelomate animals used to force food down the digestive tract. Nematodes thus depend on internal/external pressures and body movement to move food through their digestive tracts. The mouth is often surrounded by various flaps or projections used in feeding and sensation. The portion of the body past the anus or cloaca is called the "tail." The epidermis secretes a layered cuticle made of keratin that protects the body from drying out, from digestive juices, or from other harsh environments, as well as in some forms sporting projections such as cilia that aid in locomotion. Although this cuticle allows movement and shape changes via a hydrostatic skeletal system, it is very inelastic so does not allow the volume of the worm to increase. Therefore, as the worm grows, it has to moult and form new cuticles. The cuticles don't allow volume to increase so as to keep hydrostatic pressure inside the organism very high. For this reason, the roundworms do not possess circular muscles (just longitudinal ones) as they're not required. This hydrostatic pressure is the reason the roundworms are round.\nMost free-living nematodes are microscopic, though a few parasitic forms can grow to several meters in length. There are no circular muscles, so the body can only undulate from side to side. Contact with solid objects is necessary for locomotion; its thrashing motions vary from mostly to completely ineffective at swimming.\nRoundworms generally eat bacteria, algae, fungi and protozoans, although some are filter feeders. Excretion is through a separate excretory pore.\nReproduction is usually sexual. Males are usually smaller than females (often very much smaller) and often have a characteristically bent tail for holding the female for copulation. During copulation, one or more chitinized spicules move out of the cloaca and are inserted into genital pore of the female. Amoeboid sperm crawl along the spicule into the female worm.\nEggs may be embryonated or unembryonated when passed by the female, meaning that their fertilized eggs may not yet be developed. In free-living roundworms, the eggs hatch into larva, which eventually grow into adults; in parasitic roundworms, the life cycle is often much more complicated.\nRoundworms have a simple nervous system, with a main nerve cord running along the ventral side. Sensory structures at the anterior end are called amphids, while sensory structures at the posterior end are called phasmids.\n\nhttp://en.wikipedia.org/wiki/Nematode\n\n\nHope that helps!
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Locomotion.  The setae on each segment allow the earthworm to "grip" the earth while their longitutinal and circular muscles contract the rest of the body into place to apply forward pressure to "burrow" through the earth.