Conservation is a type of Principle. Conservation is related to People. you are likely to find People in/at/on Wedding. 
Agreement is related to Mortgage. Mortgage is related to Home. Home is related to Familiar. 
Principle <--IsA-- Conservation <--RelatedTo--> People --AtLocation--> Wedding 
Agreement <--RelatedTo--> Mortgage <--RelatedTo--> Home <--RelatedTo--> Familiar 