Danger is related to Scary. Scary is related to Shock. Shock is a synonym of Impact. 
Stress is a synonym of Try. Try is related to Experiment. Experiment is related to Study. Study is related to History. 
Danger <--RelatedTo--> Scary <--RelatedTo--> Shock <--Synonym--> Impact 
Stress <--Synonym--> Try <--RelatedTo--> Experiment <--RelatedTo--> Study <--RelatedTo--> History 