Arizona State University (ASU) CSE240 Introduction to Programming Languages Midterm Practice Exam

Machine code is a low-level programming language consisting of binary instructions that are executed directly by a computer's central processing unit (CPU). Since it is composed of binary digits (0s and 1s), it corresponds closely to the hardware architecture of the machine, allowing for optimal performance when instructions are processed. This unique characteristic is what distinguishes machine code from other types of code, such as high-level languages or source code.

In contrast, machine code is not human-readable, as it is not written in a format that is easily understood; thus, the first choice is not true. Machine code is also not written in high-level programming languages; instead, high-level languages must be compiled or interpreted into machine code for execution. This makes the third choice incorrect. Finally, machine code and source code are fundamentally different; source code is written in high-level languages and requires a translation process to become machine code. Therefore, the distinction between machine code and source code emphasizes their different roles within the programming model, further confirming that the correct answer revolves around the nature of machine code as binary instructions directly executable by hardware.