The given function for population growth is $F = 3.9(1.023)^t$, which represents exponential growth.

In this equation:

• $F$ is the future population size.
• $3.9$ represents the initial population size.
• $1.023$ is the growth factor.
• $t$ is the time in years.

To determine the growth rate:

The growth rate can be found from the growth factor, which is $1.023$. The growth factor is written as: $\text{Growth Factor} = 1 + \text{Growth Rate}.$ In this case: $1.023 = 1 + \text{Growth Rate}.$ So, the growth rate is: $\text{Growth Rate} = 1.023 - 1 = 0.023 = 2.3\%.$

Conclusion:

The correct answer is D: The population is growing at a rate of 2.3%.

Would you like any more details or have any other questions? Here are some related questions to further your understanding:

1. How is the growth factor used in exponential functions to represent growth or decay?
2. What is the general formula for an exponential growth model?
3. How can you convert a growth factor into a percentage growth rate?
4. How would the function change if the population were declining instead of growing?
5. How does the initial population size affect the shape of the exponential growth curve?

Tip: In exponential growth, if the growth factor is greater than 1, it indicates growth. If it is less than 1, it indicates decay.