The general form of exponential function is given below:
[tex]\begin{gathered} y=a.b^x+c \\ \text{When a.b}^x=0,\text{ the asymptote of the function becomes } \\ y\text{ = c , which is, y-intercept} \\ \text{But where c=0, the asymptote is the line y = 0} \end{gathered}[/tex]