The independent variable would be the variable in the research that is being manipulated by the researcher. In this case, it would be temperature in the cage as it is what is being manipulated and changed in the research design. The dependent variable would be the variable that is being studied so, for this case, it would be the length and the weight of the mice. The constants are the factors that might affect the dependent variable but is held constant or the same by the researcher throughout the experiment. These are the size of the cage, amount of food and the exercise wheel. The flaw that the scientist would be studying the length of the mice since I don't think the temperature has any effect on it. And base from he results, the change in lengths are not conclusive.
Answer: Balanced molecular equation :

Total ionic equation:
The net ionic equation:

Explanation:
Complete ionic equation : In complete ionic equation, all the substances that are strong electrolyte are present in an aqueous state as ions.
Net ionic equation : In the net ionic equations, we are not include the spectator ions in the equations.
Spectator ions : The ions present on reactant and product side which do not participate in a reactions. The same ions present on both the sides.
When sodium phosphate and zinc acetate then it gives zinc phosphate and sodium acetate as product.
The balanced molecular equation will be,

The total ionic equation in separated aqueous solution will be,

In this equation, and are the spectator ions.
By removing the spectator ions from the balanced ionic equation, we get the net ionic equation.
The net ionic equation will be,

I don’t know what exactly is but see at the picture.
Answer:
8.0356 * 10^-5 moles of NaHCO3
Explanation:
Sulphuric acid = H2SO4
Sodium bicarbonate = NaHCO3
The reaction between both compounds is given by;
2NaHCO3(aq) + H2SO4(aq) → Na2SO4(aq) + 2CO2(g) + 2H2O(l)
In the reactin above;
2 mol of NaHCO3 neutralizes 1 mol of H2SO4
At stp, 1 mol occupies 22.4 L;
1 mol = 22.4 L = 22400 mL
x mol = 0.9 mL
x = 0.9 / 22400 = 4.0178 * 10^-5 moles of H2SO4
Since 2 mol = 1 mol from the equation;
x mol = 4.0178 * 10^-5
x mol = 2 * 4.0178 * 10^-5
x = 8.0356 * 10^-5 moles of NaHCO3