Size is a type of Classify. Size is related to Clothes. 
Child is related to Support. Support is related to Strength. Strength is related to Rest. you would Rest because Weak. 
Classify <--IsA-- Size <--RelatedTo--> Clothes 
Child <--RelatedTo--> Support <--RelatedTo--> Strength <--RelatedTo--> Rest --MotivatedByGoal--> Weak 