Theories are defined as

A) testable propositions.
B) factors that may change in response to manipulation.
C) statistical indexes.
D) principles that help to organize observations and predict behaviors or events.

Testable Propositions

Statements or hypotheses that can be empirically tested through observation or experimentation to evaluate their validity.

Principles

Fundamental truths or propositions that serve as the foundation for a system of belief or behavior or for a chain of reasoning.

Behavioral Predictions

The process of forecasting individual or group behaviors based on past actions, trends, or patterns.