Necessary is related to Important. Important is related to Conservation. Conservation is related to Preserve. Preserve is a synonym of Save. 
Winter is related to Bear. Bear is a synonym of Behave. 
Necessary <--RelatedTo--> Important <--RelatedTo--> Conservation <--RelatedTo--> Preserve <--Synonym--> Save 
Winter <--RelatedTo--> Bear <--Synonym--> Behave 