Step-by-step explanation:
Hades is a god of the under world/earth.
Demeter a goddess of the upper world/earth.
So, both deal in the earth, one below one above.
Hades was later associated with plant life and growth, for when Persephone rose from the underworld he had released spring.
Hades and Demeter were brother and sister, their mother was Rhea, and father Cronus.