31. Two students collect information about the number of dandelions in a park. Based on their sampling, they estimate that there are 900 dandelions in the 300-square-meter city park. To determine the accuracy of their estimate, which of the following questions is necessary?

A. What was the range of sizes among the sampled dandelions?
B. How many samples were taken to determine the estimate?
C. What time of day was the sampling conducted?
D. Were the dandelions distributed only in grassy areas?

I think it's C because night-time could affect the outcome

No. I think dandelions bloom the same all day and night.

To determine the accuracy of the students' estimate, we need to consider factors that could potentially affect the sampling process. Out of the given options, option C asks about the time of day during which the sampling was conducted, which could indeed impact the outcome.

However, it's important to note that option C alone might not be sufficient to evaluate the accuracy of the estimate. Time of day is just one factor, and there could be other factors that affect the estimate as well. Let's consider the other options:

- Option A asks about the range of sizes among the sampled dandelions. This information can give us insights into the variability of the dandelion population, which is relevant to determining the accuracy of the estimate.

- Option B asks about the number of samples taken. The more samples taken, the more representative the estimate can be. This information is also crucial in evaluating the accuracy of the estimate.

- Option D asks whether the dandelions were distributed only in grassy areas. If the sampling was biased towards grassy areas, the estimate may not accurately represent the entire park.

Considering all these factors, a more comprehensive approach would involve considering options A, B, and D along with option C to assess the accuracy of the estimate.