In the exponential function of the form \( y = a \cdot b^x \), the value of \( b \) represents the growth factor if \( b > 1 \) or the decay factor if \( 0 < b < 1 \).
- If \( b > 1 \): The function models exponential growth, meaning that the value of \( y \) increases as \( x \) increases.
- If \( 0 < b < 1 \): The function models exponential decay, meaning that the value of \( y \) decreases as \( x \) increases.
Thus, the correct answer is that \( b \) can represent either a growth factor or a decay factor, depending on its value. However, if you need to choose one from the options provided, "growth factor" is typically the term used when \( b > 1 \).