Boil is a synonym of Burn. Burn is related to Injury. Injury is a synonym of Trauma. Trauma is related to Wound. 
Bulb is related to Smell. Smell is related to Working. Working can cause/lead to Reward. Reward is related to Missing. 
Boil <--Synonym--> Burn <--RelatedTo--> Injury <--Synonym--> Trauma <--RelatedTo--> Wound 
Bulb <--RelatedTo--> Smell <--RelatedTo--> Working --Causes--> Reward <--RelatedTo--> Missing 