Let's analyze the given data step-by-step to determine the population trend of "species Z":
1. Birthrate: This is the number of individuals added to the population per year due to births. For "species Z," the birthrate is given as 7.
2. Deathrate: This is the number of individuals lost from the population per year due to deaths. For "species Z," the deathrate is given as 2.
3. Immigration Rate: This is the number of individuals coming into the population from other areas per year. For "species Z," the immigration rate is given as 4.
4. Emigration Rate: This is the number of individuals leaving the population to move to other areas per year. For "species Z," the emigration rate is given as 6.
We need to calculate the net growth rate of the population by considering both the birthrate and the immigration rate, and then subtracting the deathrate and the emigration rate.
First, let's combine the birthrate and immigration rate:
[tex]\[ \text{Total increase in population} = \text{birthrate} + \text{immigration rate} = 7 + 4 = 11 \][/tex]
Next, let's combine the deathrate and emigration rate:
[tex]\[ \text{Total decrease in population} = \text{deathrate} + \text{emigration rate} = 2 + 6 = 8 \][/tex]
Now, subtract the total decrease in population from the total increase in population to find the net growth rate:
[tex]\[ \text{Net growth rate} = \text{Total increase} - \text{Total decrease} = 11 - 8 = 3 \][/tex]
The net growth rate of 3 indicates that the population is increasing by 3 individuals per year.
Given this net growth rate, we can determine the population trend:
- If the net growth rate is positive (greater than 0), the population is increasing.
- If the net growth rate is negative (less than 0), the population is decreasing.
- If the net growth rate is zero, the population remains constant.
Since the net growth rate is 3, which is positive, the population trend of "species Z" is increasing.
Therefore, the best explanation for what is happening in the population of "species Z" is:
O The population is increasing
