There is no such thing. But if you read Percy Jackson books, you may learn more Greek mythology.
Demeter never got married but she did get a baby with Zeus.
Zeus is the brother of Demeter
Demeter is Zeus' older sister
Demeter had one daughter with Zeus: Persephone.
Persephone's parents are Zeus and Demeter.
Zeus and Demeter were not lovers. Demeter bore a daughter by Zeus named Persephone (Kore), however Zeus married his other sister, Hera. (Note that Zeus mated with many other goddesses and mortals, not just his lover and Demeter)
No. Demeter is the daughter of Kronos and Rhea. She and Zeus are siblings.
Demeter and Zeus did not marry, but did have the child Persephone/Kore.
Yes, Demeter and Zeus were lovers. They produced a daughter Persephone.
Zeus has three sisters: Hera (who is also Zeus' wife), Hestia and Demeter.
Demeter and Hestia were her sisters. She also had three brothers Zeus, Poseidon, and Hades.
There was only one child between Zeus and Demeter, and that was Persephone.