These are two Abstract Algebra problems, that I need help with please. I need help with the solution and the proof which is what the reflective narrative is asking for. Please make it legible.

3. Suppose a and b belong to a commutative ring and ab is a zero-divisor. Show that either a or b is a zero-divisor. Solution Reflective Narrative 4. Suppose that G is a finite abelian group. Prove that G has order p", where p is prime, if and only if the order of every element of G is a power of p. Solution Reflective Narrative