Nation is related to Language. Language is related to Example. Example is a synonym of Exercise. you would Exercise because Improve. 
Vulnerable is the opposite of Strong. Strong is the opposite of Light. 
Nation <--RelatedTo--> Language <--RelatedTo--> Example <--Synonym--> Exercise --MotivatedByGoal--> Improve 
Vulnerable <--Antonym--> Strong <--Antonym--> Light 