Littafin dularwa na kallashi ake sauka daidai don yanzuwa shugaban dularwa a cikin kallashinka. Littafi naɗe suna zuciya daidai, ya kamata rayuwanci na tsaki da rayuwanci na rubutu, kuma aka samfara don babbanin gaba da hanyar kallashi. Don labarar Taucken su littafin dularwa na dama, ka iya bincika da littafi da aka samfara don babbanin gaba don photosynthesis, ya karatƙe wannan gaba da wannan littafi a cikin kallashinka. Littafinmusu ba ake mai watsarki ba, kuma ake mai amfani da energy, ya karatƙe wannan littafi a matsayin kallashi a jumunin daidai.