Answer:
The independent variable (IV) is the characteristic of a psychology experiment that is manipulated or changed by researchers, not by other variables in the experiment.
For example, in an experiment about the effect of nutrients on crop growth: The independent variable is the amount of nutrients added to the crop field. The dependent variable is the biomass of the crops at harvest time.
Therefore : 3. the variable that responds to what the scientist changes in an experiment
Answer:

Explanation:
Hello there!
In this case, when referring to single replacement reactions, it is crucial for us to figure out the formula of the starting reactants; thus, we know zinc is Zn and lead (IV) chloride is PbCl₄. In such a way, the reaction proceeds as follows:

Which must be balanced as shown below:

Regards!
Answer:
the answer is very correct as AgNO3 and Cu(NO3)2