Answer
$\text{exponential decay;}$
$y$-intercept = $0.5$
Work Step by Step
Recall:
The exponential function $y=c \cdot b^x$ involves:
(1) an exponential growth if $b\gt1$.
(2) an exponential decay if $0\lt b \lt1$.
The given exponential function has $b=\frac{1}{4}$, which is less than $1$.
Thus, the function is an example of an exponential decay.
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&=0.5\left(\frac{1}{4}\right)^0\\
y&=0.5 \cdot 1\\
y&=0.5
\end{align*}
