Doubt is a type of Emotion. Emotion is part of Mind. Mind is related to Memory. Memory is related to Brain. 
Scheme is a type of Plot. Bed is a type of Plot. Bed is related to Box. 
Doubt --IsA--> Emotion --PartOf--> Mind <--RelatedTo--> Memory <--RelatedTo--> Brain 
Scheme --IsA--> Plot <--IsA-- Bed <--RelatedTo--> Box 