In Voltage divider bias , we are not drawing any electrons from the base. Then how can the electron current pass through the base and go to the collector and reach the positive terminal. Only if You draw electrons from the base by maintaining the base at positive potential, then only the electrons from Vcc can flow through the base and to the collector and reach the positive terminal of Vcc. The need for removal of electrons from the base is that. In the first circuit shown, when the base emitter is forward biased, the holes in the P region diffuse into the N region and the holes in the base are now filled by electrons as a result the base becomes the negatively charged. Now the electrons from Vcc negative terminal cannot pass through the transistor as they have to cross the base which is now negatively charged . But since the base is made positive the electrons that filled up the holes are attracted as a result the base now consists of holes and the electrons from - Vcc can now flow through the transistor . Since in Voltage divider bias this provision( Vbb) is not there , then how can electrons be withdrawn from the base and how can current flow through the transistor.