They were siblings and worked together when necessary. Together they killed all the children of Niobe, when they thought she had insulted their mother. They both loved their mother, Leto, and each other. Apollo protected Artemis's and her followers' virginity. Artemis would avenge Apollo if he was insulted.
Addition: The last comment has nothing to do with the question.
They are siblings, and usually they don't get along. They are opposites in their powers, and plus the whole you-don't-get-along-with-siblings thing. Artemis thought Apollo was irresponsible. Apollo thought Artemis was too mature.
No, however in the myth of the war of Troy they are rivals for the Apple of Discord inscribed "for the fairest".
They were not jealous of each other, if that is what you mean.
Yes; she was involved in the fighting in the Titan war, and that of the Giants.
Yes, because as they're half siblings, their father, Zeus demanded peace. (Random answer :P)
The goddess Artemis does not have a husband or any children. She is a virgin goddess.
Artemis is a virgin goddess.
Any forest she wanted, for Artemis is goddess of all the wilderness of the world.
The Greek goddess Artemis never had any child, being a virgin goddess.
First off, Artemis was a Greek goddess. She did not have any children because she was a virgin goddess.
no Artemis was not a violent goddess
No, the goddess Artemis did not marry. She was a virgin goddess.
Artemis the Greek goddess never went to any school.
Yes, Artemis was a goddess of childbirth.
Artemis was the female goddess of hunting.
The goddess Artemis did not have a spouse. She was a virgin goddess.
No. Since Artemis is a virgin goddess, she can't have any demigod children.