Answer
$\text{exponential growth}$
$y$-intercept = $1$
Work Step by Step
Recall:
The exponential function $y=c \cdot b^x$ involves:
(1) an exponential growth if $b\gt1$; or
(2) an exponential decay if $0\lt b \lt1$.
The given exponential function has $b=5$, which is greater than $1$.
Thus, the function is an example of exponential growth.
The $y$-intercept of an exponential function can be found by setting $x=0$ then solving for $y$.
Hence, the $y$-intercept of the given function is:
\begin{align*}
y&=5^0\\
y&=1
\end{align*}