1-Option A. Current model will be revised.
2-Option D. Nucleus
3-<span>Option B. </span>Counting the no. of protons.
The type of reaction of Fe2O3 + 2SiO2 → Fe2Si2O7 would be that it is a synthesis reaction. It is a type of chemical reaction in which two or more simple substances combine to form a more complex product. Hope this answers the question.
One of the most likely products for the reaction would be 
<h3>Chemical reactions</h3>
The reaction between
and
yields 3 products which are
(a precipitate),
, and
as shown by the equation below:

One of the products precipitates out of the solution to give the reaction a precipitation reaction look.
More on precipitation reaction can be found here: brainly.com/question/24158764
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<span>Among important crop plants, nitrogen-fixing root nodules are most commonly an attribute of
B) legumes</span>
The term formula units means molecules.
Then, what you are looking for is the mass in 4.59*10^24 molecules.
The procedure involves to convert the 4.59 * 10^24 molecules into moles and use the molar mass of the sodium chloride.
1) Number of moles = 4.59 * 10^24 molecules / (6.02 * 10^23 molecules/mol) = 7.62 mol
2) Molar mass of NaCl = 22.99 g/mol + 35.45 g/mol = 58.44 g/mol
3) mass of NaCl = molar mass * number of moles = 58.44 g/mol * 7.62 mol = 445.31 g of NaCl
Answer: 445.31 g of NaCl.