Which day range indicates a negative growth rate for the Daphnia population?

• A. From about day 1 to day 30
• B. From about day 70 to day 105
• C. From about day 150 to day 200
• D. From day 200 to day 260

Answer: (B)

Negative growth rate means the population is shrinking over time, so the interval you’re looking for is when the Daphnia number falls as days pass. In the period from about day 70 to day 105, the population decreases, indicating a negative growth rate during that window. This decline happens when deaths exceed births or when individuals leave the population faster than new individuals are added, causing the curve to slope downward. The other day ranges show the population increasing or remaining stable, so their growth rates are positive or zero.