Scientists should control most possible variables in experiments to get the most valid and correct data. If many variables are included in experiments it is more difficult to interpret what is causing a different outcome.
<span>Ethanol is delicious when consumed as a drink. Methanol must be avoided, however, because of it making you go blind. Gasoline and diesel are the best fuels for vehicles.</span>
<em><u>Larger molecules take longer to move up the chromatography paper or TLC plate, whereas smaller molecules are more mobile. Likewise, the polarity of the molecules can affect how far the spots travel, depending on the type of solvent used.</u></em>

The reason you are holding on to that might be because you have hope that this person who left you might come back. If they left you they aren't worth hoping for them to come back. This is a question that probably should be asked elsewhere but hope I can help.
Answer:
The correct option is
B. PEA = KEC + PEC
Explanation:
The potential energy is the energy possessed due to position
From the image the point with the highest position and therefore the most potential energy and the lowest or zero kinetic energy is point A
Given that we have;
Total mechanical energy = The potential energy + The kinetic energy
Where there is constant total mechanical energy in the system, then, at the point A where the kinetic energy is zero, the potential energy is equal to the total mechanical of the system, we have;
Total mechanical energy = The potential energy at A = PEA
Total mechanical energy = PEA
At point C where we have the total mechanical energy presented as follows;
Total mechanical energy = Kinetic energy at C + Potential energy at C
Total mechanical energy = KEC + PEC
Therefore;
PEA = KEC + PEC.