Mbere ya byose, ubuso bwumuringa muremure cyane buzakora urwego rukingira, nubwo rwaba amavuta, karubone, bagiteri na mikorobe, amazi yangiza, ogisijeni cyangwa imirasire ya ultraviolet, ntishobora kunyuramo, cyangwa ntishobora kurandurwa kugirango yanduze ubwiza bwamazi, kandi parasite irashobora ...
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