Each compound will be neutral
This is a symbiotic relationship called commensalism if the tree root is the only one to benefit.
The reaction is endothermic as energy is absorbed to break a bond.
Convert grams —> mols and then mols —> atoms
We know that there are 6.02 x 10^23 atoms/mol
And we know that there are about 160 grams of fe2o3 per mol
So (79g fe2o3)/(160 g/mol) = .49 mol fe2o3
Now we use avogadro’s number to do
(.49 mol fe2o3)/(6.02 x 10^23 atoms/mol) = the answer.
I’ll leave the easy math to you.
The independent variable would be the amount of sunlight because that is what you are testing and the dependent variable would be the length of time the mice slept because it is what you are measuring. The constants would be everything else water, food, cage size, exercise wheel, and temperature because they stay the same.