*Question*
Q: Resonance has been used in what kind of human-made recreational objects since prehistoric times? Choices: - toys - paintbrushes - arrows - musical instruments A:
**Answer**
musical instruments

*Question*
Q: Which theory explains how populations of organisms can change over time? Choices: - free by natural selection - changes by natural selection - intelligent selection - evolution by natural selection A:
**Answer**
evolution by natural selection

*Question*
Q: Which area of the human heart pumps the blood to the right ventricle? Choices: - left atrium - true atrium - left ventricle - right atrium A:
**Answer**
right atrium

*Question*
Q: Gibbs free energy values can be used to determine what? Choices: - equilibrium differentials - prime constants - equal lines - equilibrium constants A:
**Answer**
equilibrium constants