M'zaka zaposachedwapa, ndi chitukuko chopitilira cha Sci. & Tech, ulimi wa ziweto wachikhalidwe wabweretsanso chitsanzo chatsopano. Mwachitsanzo, masensa osiyanasiyana amayikidwa mu famu ya ziweto kuti aziwunika mpweya wa ammonia, chinyezi, kutentha ndi chinyezi, kuwala, zinthu...
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