Back bone-the column of vertebrea( bones )in the back.
Ball-and-socket Joint-a joint in which a rounded bone can move in all directions.
Bar Graph-a graph that uses parallel bars whose lengths are in proportion to the numbers they represent.
Barometer-an instrument that measure air pressure and is used to predict changes in the weather.
Base-the bottom of a shape.
Battery-an electric cell for providing an electric current or a group of those cells.
Borrow-to take one from the digit to the left to make subtraction easier.