Answer: A. What causes trees to lose their leaves in the fall?
Step-by-step explanation:
A scientific question is a question that can be answered through scientific investigation, data collection, and analysis. The question "What causes trees to lose their leaves in the fall?" is a scientific question because it can be studied through observation, experimentation, and data analysis to develop a better understanding of the process. This type of question allows for a systematic and empirical approach to uncover the underlying mechanisms behind the phenomenon being studied. In contrast, questions B, C, and D are personal opinions or subjective preferences, and therefore not amenable to scientific investigation.