Final answer:
A testable hypothesis can be developed from the question 'What makes a baseball bounce?'.
Step-by-step explanation:
A testable hypothesis is a statement that can be tested or investigated through observation and data collection. From the given options, the question 'What makes a baseball bounce?' could be developed into a testable hypothesis. For example, 'Increasing the air pressure inside a baseball will increase its bounce height.' This hypothesis can be tested by conducting experiments and measuring the bounce heights of baseballs with different air pressures.
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