Im not quite positive, but i think it is because the players would need something to keep the ball from going foul, or to get an easier shot at making the basket!:)
You can take a large piece of wood and cut in in a rectangle or in the shape of a backboard.
The basketball backboard is there to show ppl where to shot the ball to get it in.
the backboard was invented in the 1900s
If the ball bounces off the backboard or rim and you catch it before it hits the ground it counts as a rebound.
If a player shoots and it doesn't hit the backboard or rim, and they catch it before it hits the floor, it's a travel. The ball either has to: a) Hit the rim or backboard. b) Hit the ground before the player can retain possession again.
goaltending
Yes
Not all lay-ups hit the backboard for example a finger roll.
only if the ball comes off of the rim or backboard of the basket
a rebound
The backboard.
no