Explanation: In a typical microprocessor system, such as one used in a RADAR, the **Memory** unit stores program instructions and data, while the **I/O (Input/Output)** unit provides the interface for the microprocessor to interact with the outside world. These units are crucial for communicating with **peripherals**, which are external devices connected to the system. For a RADAR, peripherals might include analog-to-digital converters for processing radar returns, display drivers, or control panels. Conversely: * The **ALU (Arithmetic Logic Unit)** performs arithmetic and logical operations, not address decoding (A). Address decoding is handled by dedicated logic that selects specific memory or I/O locations. * The **Control Unit** directs and coordinates the operations of the processor, fetching instructions and generating control signals. Arithmetic manipulations are executed by the ALU (C). * The **internal bus** is a shared communication pathway within the microprocessor. While various units use it, they generally access it sequentially, not simultaneously, to avoid data collisions (D).