Mean is a synonym of Little. Little is related to Name. Name is related to Physician. Physician is the opposite of Nurse. 
Nature is related to Calm. Calm is related to Lake. you are likely to find Bacteria in/at/on Lake. 
Mean <--Synonym--> Little <--RelatedTo--> Name <--RelatedTo--> Physician <--Antonym--> Nurse 
Nature <--RelatedTo--> Calm <--RelatedTo--> Lake <--AtLocation-- Bacteria 