Answer: this is because nutrients are increased by the movement of water.
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Explanation:
For a compound to show hydrogen bonding it is necessary that the hydrogen atom of the compound should be attached to more electronegative atom like fluorine, oxygen or nitrogen.
For example, 
, 
and 
all these compounds contain an electronegative atom attached to hydrogen atom.
Therefore, these pure compounds will exhibit hydrogen bonding.
Thus, we can conclude that out of the given options , and are the pure compounds which will exhibit hydrogen bonding.
In the choices above, the correct letter of the question is letter a, scintillation counter. It is because it uses a phosphor-coated surface in order to use its function in detecting radiation. Its component could produce bright flashes where it will be sufficient in detecting the radiation.
For a candle to burn, it requires a spark, which provides the activation energy for the oxidation reaction of the hydrocarbon making the candle.
It also requires oxygen to facilitate the oxidation of the hydrocarbon.
Therefore the two main requirements of combustion of a candle are oxygen and a spark (or an initial flame)
