For $y=x-x^5,$ determine intervals on which the function is increasing, decreasing, concave up$,$ and concave down; relative maxima and minima; inflection points; symmetry; and those intercepts that can be obtained conveniently. Then sketch the graph.

On which interval$($s$)$ is the function decreasing? Select the correct choice below and, if necessary, fill in the answer box to complete your choice.

A$.$ The function is decreasing on $|.$

$($Type your answer in interval notation. Simplify your answer, including any radicals. Use integers or fractions for any numbers in the expression. Use a comma to separate answers as needed.$)$

B$.$ The function is never decreasing.