Areas with poor drainage system
The number of repetitions per second is called the frequency and is the inverse of the period. The period, T, is normally measured in seconds, and the frequency, ν, in Hertz. When the oscillations<span> (or vibrations) affect the material around them a </span>wave <span>is formed which transports energy away.</span>
<em></em>Your answer is :<em>
A.
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Groundwater.<em>
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The standard states of elements are the forms that they adopt at a temperature of 25°C and pressure of 1 atmosphere. These forms of the elements are the reactants in the formation equations of multi-element substances. The heat of formation (∆Hf°) of an element in its standard state is zero
Yes your right the answer is D
