In cases like these, you simply have to multiply the choices you have for each step.
In fact, you can choose between 4 different crusts. For each of these crusts you can choose 4 different sauces. This means that there are choices at this point. In fact, if we call the crust options 1,2,3,4 and the sauce options A,B,C,D, the 16 possible combinations are
From here, you keep going multiplying the number of options for each step, for a total of
The population function of the Western Lowland Gorillas can either represent population growth or population decay
<h3>How to model the population</h3>The question is incomplete, as the resources to model the population of the Western Lowland Gorillas are not given.
So, I will give a general explanation to solve the question
A population function can be represented as:
Where:
From the question, we understand that the population of the Western Lowland Gorillas decreases.
This means that the rate of the function would be an exponential decay i.e. 1 -r
Take for instance:
By comparison.
a = 2000 and 1 - r = 0.98
The above function can be used to model the population of the Western Lowland Gorillas
Read more about exponential functions at: