(SPOILER)
21. How many forms of "Jenova" do you fight in the game?
Four. BIRTH, LIFE, DEATH and SYNTHESIS.
22. Where does Aerith keep the Holy materia?
In her hair. Maybe even her hairband.
23. Where can you find the Fourth Bracelet?
Dunno. Forgot that thing even existed until you mentioned it just now.
24. What color Chocobo is needed to receive the Knights of the Round materia?
Gold
25. What is the name of Barret's wife?
Myrna