*Question*
Q: What is it called when waves spread out as they travel around obstacles or through openings in obstacles? Choices: - absorption - destruction - diffusion - diffraction A:
**Answer**
diffraction

*Question*
Q: What is the wavelength of light expressed in? Choices: - nanoseconds - millimeters - vatts - nanometers (nm) A:
**Answer**
nanometers (nm)

*Question*
Q: What happens when a neutral atom gains or loses electrons? Choices: - it loses protons - it gains protons - it loses neutrons - it becomes an ion A:
**Answer**
it becomes an ion

*Question*
Q: How does a reduced sweating ability affect elderly people? Choices: - loss of mental ability - extreme tiredness - less energy - extreme heat intolerance A:
**Answer**
extreme heat intolerance