Final answer:
In a BJT C-E amplifier circuit with normal base-emitter bias, if the base current falls, both collector current and emitter current will also fall.
Step-by-step explanation:
In the operation of a Bipolar Junction Transistor (BJT) configured as a common-emitter (C-E) amplifier, the base-emitter junction is usually forward-biased, meaning that it is connected to allow current flow from the emitter to the base. This biasing establishes the operating point of the BJT and allows it to amplify signals. When the base-emitter is normally biased, if the voltage across the base-emitter junction increases (leading to an increase in base current), it allows more electrons to flow from the emitter to the collector, therefore increasing the collector current. If the base current falls, this would reduce the number of electrons capable of contributing to the collector current, and hence the collector current (Ic) will also fall. Consequentially, since the emitter current (Ie) is the sum of the base current (Ib) and the collector current, it will also fall.