Whatever the statement is, I know one thing for sure: It's NOT included on the list of choices that you've provided.
Explanation:
Everything in Earth's system can be placed into one of four major subsystems: land, water, living things, or air. These four subsystems are called "spheres." Specifically, they are the "lithosphere" (land), "hydrosphere" (water), "biosphere" (living things), and "atmosphere" (air).
Answer:
v = 10 m/s
Explanation:
recall that velocity is related to wavelength and frequency by the formula
v = fλ
where v = velocity, f = frequency and λ= wavelength
Simply substitute these into the formula:
v = fλ
v = (0.5)(20)
v = 10 m/s