血液(Blood)

详细内容

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whatisblood?itistheredliquidwhichesoutofyourfingerwhenyoucutitbecauseofnotbeingcarefulthereareabout13pints(品脱)ofbloodinaman＇sbody.hecangiveapfntofmoodatatimetoamoodbankfortheuseaothermanwhomayneedit.ahealthybodymakesupthepintofbloodquickly.whatdoesourblooddoforus?ittakesfoodtoallpartsofourbodiesandtakeswasteawayfromthem.ailthepartsofourbodiesaremadeupofcells,thesecells,whichareverysmall,allneedfoodallthetime.thebloodislikeastream.thecellstakewhattheyneedoutofthemoodstream,asplantsandfishestaketheirfoodoutofwater.thebloodstreamcarriesfoodandtheoxygenwhichithastakenupinourlungstoailthecellsinthebody.

whatmakesthemoodgoonmovingroundthebodyinastream?theheartsendsitround.theheartkeepsastreamofbloodgoingallaroundthebodyandbackagaintoitself.everywherethemoodstreamdoestwothings:suppliesthecellswithfoodandoxygenandtakesawaywaste.itisasifthemoodkeptthelittlefiresincellsburningandtookawaytheashes.