Final answer:
A nurse conducting theory testing and development research for nursing science is likely to have a doctoral degree, which is the level of education that focuses on research and contributions to the profession's body of knowledge.
Step-by-step explanation:
A nurse involved in theory testing and theory development research to advance nursing science is typically prepared at the doctoral degree level. This level of education focuses on research and development within a particular field to contribute to the body of knowledge, which is essential for a profession such as nursing that relies on evidence-based practices.