related
She studied temples in Israel and Egypt, finding strong similarities that she believes back up her theories about the closely related cultures.
Many studies have shown that students dropping out of school is closely related to teen pregnancy.
Although the incidents are superficially similar, investigators do not suspect them to be closely related.

SMART Vocabulary: related words and phrases

Linking and relating
affiliated
AL
appertain to something
applicable
around
attach
collateral
equation
interconnected
interconnectedness
interconnection
intercorrelate
intercorrelation
relatability
relatable
relate
relate to someone/something
relatedly
relation
tar