Q: Q: When a wave travels down a string, the string vibrates up and down at right angles to the wave's what? Choices: - frequency - pressure - gravity - direction A:
A: direction

Q: Q: What chemical element is required for a combustion reaction ? Choices: - carbon - helium - nitrogen - oxygen A:
A: oxygen

Q: Q: What is the biggest risk associated with using nuclear energy? Choices: - explosion - mutation - fire - radiation A:
A: radiation

Q: Q: A bicycle is an example of a compound machine made of many what? Choices: - linked machines - useful machines - interchangeable machines - simple machines A:
A: simple machines