Because if they are not balanced, then the amount of reaction is not equal to the amount of the product. You must have the same ratio of atoms on both sides of the equation because we are not losing moles of each element.
I would assume it would be impossible or unlikely
You can't usually just use a single spectrum line to confirm the identity of an element because there are cases that the emission line id not clearly defined. When the emission line is very weak compared to surrounding noise, in which case the more datapoints you have to build up confidence for the existence of a particular emission spectra, the better.
Answer:
all
Explanation:
it can be from all as some plants are hydrotrophic i.e. they get attracted to water but some get away from water. Same sunflower faces sun from morning to evening but some plants get burnt while in sun.
