The abstract generalization that presents a systematic explanation about the relationship among phenomena is called a theory.

Here's why:

* Abstract: Theories are not concrete or specific; they deal with general concepts and principles.

* Generalization: They apply to a broad range of situations or events, not just one specific instance.

* Systematic Explanation: Theories provide a structured and organized account of how things work, identifying the key elements involved and their relationships.

* Relationship Among Phenomena: Theories aim to explain how different aspects or events are connected and influence each other.

Example: The theory of gravity explains the relationship between mass and the force of attraction between objects. This is a general explanation that applies to all objects with mass, not just specific examples.

Let me know if you'd like to explore any specific theories or concepts further!