C) studying seismic waves
AKA what is studied from earthquakes
Answer:
when a element of 1 group take part in reaction, its atom looses outer electron and form positively charged ions called Cation.
Explanation:
In physics, there are empirical values for common important parameters. For example, the speed of sound is equal to 340 meters per second. Unlike the speed of light, the speed of sound is dependent on temperature and pressure. But in standard room conditions, the speed is 340 m/s. Using this value of speed, we can find the depth given the time. You should also note that the distance the echo travels is exactly the same distance that object travelled. Therefore,
Distance = 340 m/s * 6 seconds
Distance = 2,040 meters deep
Answer
given,
Q u = 8.7 m³/s
Q d= 0.9 m³/s
BOD concentration = 50 mg/L
a) BOD concentration at the down stream
= 4.69 mg/L
b) discharge = 9.6 m³/s
cross sectional area = 10 m²
velocity steam = 
= 0.96 m/s
time taken to move 50 km down stream =
= 52083.3 s
= 
= 0.6 days
now,
