What's that?
It is a backpack./ a bag.
What's that?
It is a crayon.
What's that?
It is a pencil.
What's that?
It is an apple.
What's that?
It is an eraser / a rubber.
What's that?
It is a marker.
What's that?
It is a ball.
What's that?
It is a ruler.
What's that?
It is a book.