Threat, or Aggro, is a caused by dealing damage, healing a player that has caused threat or using a spell or ability that generates threat. The creature, in most cases, attacks the player with the...
The damage of a spell is more than just the number on the tooltip, so this question cannot be answered directly. All spells have a base damage range, and some spells are also area-of-effect (AOE)....
All characters get spells every other level up to 60, then they can train every level for new spells and spell ranks. For druids, please see the Wowhead page in the related links section for all...