The answer for the first question is A. Proton is the subatomic particles which adds most of the mass of an atom as well as the neutron since they have the same mass. Photon, on the other hand, is not one of the subatomic particles.
It is a completely true statement that a <span>base increases the OH- ion concentration of water. The correct option among the two options that are given in the question is the first option. I hope that this is the answer that you were looking for and the answer has actually come to your desired help.</span>
Percent error is the difference between the measured and known value, divided by the known value, multiplied by 100%.
So first, we take our measured value, .299 cm, minus our known value, .225 cm.
.299 cm - .225 cm=.004 cm
Next, we divide that by our known value

Finally, multiply your answer by 100
.0177777778 x 100= 1.77777778 %
Round to three significant figures, and you're done.
=1.78 % error
Explanation:
Mg+O>MgO
Here the mg loses it electron and is oxidised and oxygen gains and is reduced.
Mg(2+)and O(2-)
Mg is a reducing agent it makes oxygen to be reduced while itself being oxidised and vice versa.