Is this true??? please someone give me the right answer

Acceleration is a direct result of a.) balanced forces b.) unbalanced forces c.) gravity d.) velocity

What do isotopes of uranium have the same number of? what do they have a different number of? a) same number of protons; different number of electrons b) same number of protons; different number of neutrons c) same number of electrons; different number of protons d) same number of neutrons; different number of protons

In general, are there any major differences that you can see? explain