A cikin jiki, iyawar rarrabewa tsakanin kwayoyin da suke daga jikin kwayar halitta da na wani abu na waje yana ba da damar kwayar halitta ta kasance cikin koshin lafiya ta hanyar fara wane irin aiki? Bisa ga tambayar da ta gabata, ka rubuta mahallin da ke ɗauke da amsar. Zai iya zama jumla 1 - 20. Abubuwan da ke ciki:
Dukkanin rigakafin da aka haifa da kuma dacewa sun dogara ne akan ikon tsarin rigakafi don rarrabe tsakanin kwayoyin kansu da wadanda ba na kansu ba. A cikin rigakafi, kwayoyin kansu sune abubuwan da ke cikin jikin kwayoyin halitta wanda za'a iya rarrabe shi daga abubuwan da ke cikin jiki ta hanyar tsarin rigakafi. Sabanin haka, kwayoyin da ba na kansu ba ne wadanda aka gane su a matsayin kwayoyin waje. Wani nau'in kwayoyin da ba na kansu ba ana kiransu antigens (gajere ga masu samar da kwayoyin cuta) kuma an ayyana su a matsayin abubuwan da ke ɗaure ga takamaiman masu karɓar rigakafi kuma suna haifar da amsawar rigakafi.