Unit is a synonym of Credit. Credit is related to Limit. Limit is related to Restriction. Restriction is related to Diet. 
Reaction is related to Rise. Rise is the opposite of Reduce. Reduce is a synonym of Limit. 
Unit <--Synonym--> Credit <--RelatedTo--> Limit <--RelatedTo--> Restriction <--RelatedTo--> Diet 
Reaction <--RelatedTo--> Rise <--Antonym--> Reduce <--Synonym--> Limit 