In the dark. Also in a wide open area.
Spiders spawn at night and in dark areas.
There is a plugin called World Guard that can do both. Look at related links for its download page.
You can't.
Yes.
you get carrots in minecraft from baby zombies on chickens or spiders, you have to kill them and then you will get them.
you have to kill spiders
Currently, no.
It does extra damage to spiders and cave spiders, nothing else.
Increases damage to spiders, cave spiders, silverfish and endermites.
bane of arthropods does extra damage to spiders, cave spiders, and silverfish
Kills spiders faster
When they hit you, you get poisoned for 10 seconds.