A) Heat.
Friction produces heat.
The force of gravity acts upon all objects; the Earth and the object attract. There are no springs touching the object; thus, there is no spring force. A taut rope is attached to the bucket; this is the cause of the tension force.
In ionic bonding, an arrow is often drawn on the diagram to show the direction the electrons move to form the ions.
Answer and Explanation:
The balanced chemical equations are as follows:
The chemical formula of oxalic is 
In the case when oxalic acts reacted with the water so here the oxalic acid eliminates one proton that leads to the development of mono acids
After that, the second step derives that when oxalic acid is in aqueous solution eliminates other proton so it represent the polyprotic acid
Now the chemical equations are as follows:
Elimination of one proton

Now the elimination of other proton
