Unity:The state of being one or forming a whole; in writing, it refers to the coherence and consistency of ideas throughout the text.
Transition: A word, phrase, or sentence that connects different parts of a text and helps maintain its flow; transitions ensure cohesiveness by guiding readers smoothly from one idea to another.
Logical progression: The orderly development and arrangement of ideas in a text; it ensures that each point builds upon the previous ones in a clear and coherent manner.