Youth is related to Single. Single is related to Unit. Unit is related to Description. 
Heavy is related to Laugh. Laugh is related to Emotional. Emotional is related to Smile. 
Youth <--RelatedTo--> Single <--RelatedTo--> Unit <--RelatedTo--> Description 
Heavy <--RelatedTo--> Laugh <--RelatedTo--> Emotional <--RelatedTo--> Smile 