Answer:
Beats is a phenomenon which occurs when two sound waves with different frequencies overlap each other.
Explanation:
When these two sound waves overlap, a third frequency is formed. The places where the two waves reinforces each other, constructive interference takes place and a louder sound is produced whereas, at points where destructive interference takes place a softer sound is produced.
These alternative loud and soft sounds are called beats.
Answer:
They can be relied upon to produce the same traits generation after generation
Explanation:
The potentially harmful effects of mining can be reduced by A. Flushing mines with water.

(500kg) ×

= 4000J
V = √(4000 ÷ 250) = 4 m/s
Natural gas is the answer.