Question

imagine a population of bacteria growing in a petri dish with nutrient agar, a gel that provides food and space to grow. the dish has a lid that keeps bacteria from immigrating into or emigrating out of the dish. every 30 minutes, every bacterium in the population reproduces asexually by dividing into two, which doubles the population size. this graph shows the growth of a population of bacteria over three hours. bacterial population select all the statements about this population that are supported by the graph. the bacterial populations growth rate between minutes 120 and 150 was greater than its growth rate between minutes 30 and 60. the population demonstrated linear growth. the populations growth rate increased over time. population growth was positive.

Explanation:

Step1: Calculate growth rate formula

Growth rate = $\frac{\text{Final population}-\text{Initial population}}{\text{Time interval}}$

Step2: Growth rate between 30 - 60 minutes

From the graph, at 30 minutes population is 2, at 60 minutes population is 4. Growth rate = $\frac{4 - 2}{60 - 30}=\frac{2}{30}=\frac{1}{15}$

Step3: Growth rate between 120 - 150 minutes

At 120 minutes population is 24, at 150 minutes population is 60. Growth rate = $\frac{60 - 24}{150 - 120}=\frac{36}{30}=\frac{6}{5}$
Since $\frac{6}{5}>\frac{1}{15}$, the growth rate between 120 and 150 minutes was greater than between 30 and 60 minutes.

Step4: Check for linear growth

For linear growth, the growth rate should be constant. Here growth rate is increasing (as calculated above), so it is not linear growth.

Step5: Analyze growth - rate change over time

As calculated in Step2 and Step3, the growth rate is increasing over time.

Step6: Check population growth sign

As time increases, the population values on the graph are increasing (e.g., from 2 at 30 minutes to 4 at 60 minutes etc.), so population growth is positive.

Answer:

The bacterial population's growth rate between minutes 120 and 150 was greater than its growth rate between minutes 30 and 60.
The population's growth rate increased over time.
Population growth was positive.