D all of the above
Hope it helps
The answer is hardness and brittleness. The ion discharging procedure and taking after impact on reservoir water quality file, for example, hardness, pH, conductivity, has been dissected. Comes about uncovered that the most discharge quality of various materials was touching base at the 30s after startup.
Answer:
Doppler effect
Explanation:
this means that at one point when the person running is close to the observer it will appear to run fast but slower as he moves away from the observer
