Answer:
False -
F = G M1 M2 / R^2
So F depends on M1 and M2 and as long either is not zero there will be a gravitational force between them.
Answer:
In a primary cell, two electrodes (one of copper and other of zinc) of metal atoms are used. These electrodes are dipped in an electrolyte solution that causes the metals to produce their respective positive and negative ions.
In this way, the flow of charges takes place and supply the electricity to the source.
Unlike a primary cell, a dry cell contains paste of an electrolyte instead of the solution. The contents of electrolyte paste react with each other through a chemical process and convert the chemical energy into electrical energy.
All of those! A qualitative observation is any one that doesn't include numbers. <em>Quantitative </em>observations include numbers, but not usually any other kind of information.