When you work out it helps clear your thoughts and think of nothing. It makes you feel good.
Answer:
For example, a wave with a time period of 2 seconds has a frequency of
1 ÷ 2 = 0.5 Hz.
Explanation:
The choices are confusing. Air, oil, and alcohol are fluids at any reasonable temperature. Dry cement is not.
I think it should be option (b)
