Which average wind speed do areas need to effectively power wind farms?
a: 1 mph
b: 5 mph
c: 10 mph
d: 16 mph

Generally, annual average wind speeds greater than four meters per second (m/s) (9 mph) are required for small wind electric turbines (less wind is required for water-pumping operations). Utility-scale wind power plants require minimum average wind speeds of 6 m/s (13 mph).

The average wind speed required to produce power at a wind farm is 16 m.p.h.

Explanation:

c is the answer because when something is left after something evaporates that shows the chemical change.