Determine if the polynomial \(x^4 - 2x^2y^2 + y^4\) is a perfect square. If so, factor it.

Step 1 ：First, recognize that the given polynomial has the form \(a^2 - 2ab + b^2\), which is the square of a binomial.

Step 2 ：In this case, \(a = x^2\) and \(b = y^2\). Therefore, the polynomial can be written as \((x^2 - y^2)^2\).

Step 3 ：To confirm this, expand \((x^2 - y^2)^2\) to get \(x^4 - 2x^2y^2 + y^4\), which matches the original polynomial.