Answer
y-axis,
Origin.
Work Step by Step
Even functions are symmetric about the y-axis. For example, for $y=x^{2}$, by plotting the graph, one can easily see that for positive and negative values of x, the y value is the same. Hence this is symmetric about y-axis. Odd functions are symmetric about the Origin. For example, $y=x$; by plotting the graph one can see that the graph is symmetric about the Origin.
