Answer :
Final answer:
One of the research questions, "Can people communicate with the dead through Ouija boards?", is not testable scientifically, while the others are testable biological questions.
Explanation:
"Can people communicate with the dead through Ouija boards?" is the research question that is NOT testable scientifically since it involves a phenomenon that cannot be objectively observed or measured.
On the other hand, "What is the effect of sleep on memory consolidation?", "How does the concentration of sugar affect the taste of tea?", and "Do plants grow better in natural light or artificial light?" are all testable scientific questions as they involve observable, measurable phenomena that can be investigated through scientific methods.
Learn more about Scientific Inquiry here:
https://brainly.com/question/5216287