The Central Processing Unit (CPU) of a computer is logically divided into which two main functional parts?

Introduction / Context:
The Central Processing Unit (CPU) is often described as the brain of the computer because it performs calculations and controls the execution of instructions. At a conceptual level, the CPU is divided into two major functional blocks. Knowing these parts and their roles is basic computer architecture knowledge. This question asks which components together make up the CPU in standard textbook diagrams.

Given Data / Assumptions:

• The context is a traditional von Neumann style CPU.
• The question lists the arithmetic logic unit (ALU) and control unit (CU) as options.
• Memory is treated separately from the CPU in this classification.
• We are to identify which parts the CPU consists of.

Concept / Approach:
The Arithmetic Logic Unit (ALU) is responsible for performing arithmetic operations, such as addition and subtraction, and logical operations, such as AND, OR and comparisons. The Control Unit (CU) directs the operation of the processor, fetching instructions, decoding them and coordinating activities of the ALU, registers and memory. Together, these two units form the core of the CPU in basic models. Memory and input/output units are treated as separate components. Therefore, the CPU is commonly said to consist of the ALU and the Control Unit.

Step-by-Step Solution:

Verification / Alternative check:
Most computer fundamentals textbooks define CPU as consisting of ALU and CU. Diagrams often show CPU as a box containing these two sub boxes, with buses connecting them to registers and memory. Descriptions explain that the ALU does the calculations while the CU orchestrates operations according to the program instructions. Memory is shown adjacent to but outside the CPU box. No authoritative texts claim that the CPU contains only memory or that it consists of a single unit alone. This consistent representation confirms that both ALU and CU are required to describe the CPU.

Why Other Options Are Wrong:

• Arithmetic Logic Unit (ALU) alone: Performs computations but cannot fetch or sequence instructions without the control unit.
• Control Unit (CU) alone: Directs operations but cannot carry out arithmetic or logical computations without the ALU.
• None of the above: Incorrect because the combination of ALU and CU is standard.
• Only the memory unit: Memory stores data and instructions but does not perform processing; it is not the CPU by itself.

Common Pitfalls:
Students sometimes think of the CPU as a single chip and forget to distinguish its logical components. Another confusion is to treat memory as part of the CPU because it is located physically near the processor on the motherboard. Conceptually, however, memory is a separate unit. To answer questions correctly, remember the classic breakdown: CPU = ALU + Control Unit, with memory and I/O as separate units that work closely with the CPU.

Final Answer:
The CPU consists of both the Arithmetic Logic Unit (ALU) and the Control Unit (CU) as its two main functional parts.