If PCs suspect ambush, should DM use passive or active Perception?

Given the DragonMarks are subraces, does this mean the Artificer’s Magic Item Savant allows you to ignore them?

Mending cantrip, could they use it to repair/recover ALL of their recovered arrows spent in combat vs half?

Are Polearm master + Sentinel feats very over power?

Can a rogue draw and throw two weapons every round without the Dual Wielder feat?

Cleric 2/Wizard 2 finds a 2nd level spell in a book, can he copy 2nd level wizard spell into his book?