I'm pretty sure the word you're looking for is data.
Anaphase. Anaphase<span> is the stage of </span>meiosis<span> or </span>mitosis<span> when chromosomes separate and move to opposite poles of the cell. Centromeres are broken and </span>chromatids<span> rip apart.</span>
A single variable.
In an experiment we are trying to figure out how one thing (independent) effects another thing (dependent) so we want to keep everything constant. We want that experiment to be controlled so nothing else is effecting our dependent variable. That way we can be 100% sure that any change to our dependent is due to our independent variable. Hope that makes sense
Scientific laws are created when a theory has stood the test of time and cannot be proven wrong even when there is another theory existed.