Where Is It (Where is - Where's the ______? ) (It is - It's on the ______)

A: Where's the book?
B: It's on the desk.
A: Where's the map?
B: It's on the wall.
A: Where's the computer?
B: It's on the table.
A: Where's the ruler?
B: It's on the chair.
A: Where's the pencil?
B: It's on the table.
A: Where's the clock?
B: It' on the wall.
A: Where's the notebook?
B: It's on the table
A: Where's the bulletin board?
B: It's on the wall