1. A normal face*What's behind Kakashi's mask :|
*How did deidara train his eye to counter genjutsu
*What killed Hashirama :|
*Who are Kunohamaru and Tsunade's parents(since only their grand parents are shown)
*Is Namikaze a clan
*Where is the Senju clan
*What is boil/explosion release? :|
*Why does wood drown bijuu chakra
Add your own questions
2. He tried but still wasn't able to because Sasuke tricked him multiple times
3. Mokuton requires high amounts of stamina/life force, he most likely ran out of life force at an early age due to spamming the jutsu throughout his life
4. One of Tsunade's parents is Mito and Hashirama's child, the other is unknown
5. There's no such thing as Namikaze clan
6. Senju clan settled in Konoha, most leaf shinobi would be related to them, Sakura and Minato could be examples
7. It's basically just very hot steam that can melt Susano'o ribcage but can also be used to increase physical strength
8. Because Mokuton is originally the Juubi's KKG and the Juubi's comes from the Shinju tree which was able to absorb chakra through it's roots