Let $z(x) = \sqrt{\tan\!\left(x\right)}$. Which of the following best describes its fundamental algebraic structure?
composition. A composition $f(g(x))$ of basic functions
sum. A sum $f(x)+g(x)$ of basic functions
product. A product $f(x) \cdot g(x)$ of basic functions
quotient. A quotient $f(x)/g(x)$ of basic functions
where
$f(x) =$
$g(x) =$ .