Answer:
Exponential decay
Explanation:
The general form of an exponential function is
, where P0 is the initial value, a is the base, and t is the exponent.
In your example, P0 is 1 and a is 4/5.
A function is experiencing exponential growth when a > 1.
A function is experiencing exponential decay when 0 < a < 1.
4/5 lies between 0 and 1, so the function is experiencing exponential decay.