Answer : The balanced chemical equation will be:
(i) 
(ii) 
Explanation :
Balanced chemical equation : It is defined as the equation in which total number of individual atoms on the reactant side is equal to the total number of individual atoms on product side.
Part (i):
The balanced chemical equation will be:

This reaction is a single displacement reaction in which most reactive element (potassium) displaces the least reactive element (hydrogen) form their solution.
Part (ii):
The balanced chemical equation will be:

This reaction is a single displacement reaction in which most reactive element (zinc) displaces the least reactive element (magnesium) form their solution.
A characteristic which helps an animal to live longer will generally tend to become more common in the population because as the animal produces more offspring those traits are passed down to them. Eventually it will be a common characteristic in the population.
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The answer to this is surface wave i think
<span>The </span>octet rule<span> is a chemical </span>rule<span> of thumb that reflects observation that atoms of main-group elements tend to combine in such a way that each atom has eight electrons in its valence shell, giving it the same electronic configuration as a noble gas.
Hope this helps</span>
The density is 1.12161 g/ml