Use the graph to answer the question below.

Question

The graph shows number of rotifers on the y-axis from 0 to 4500, in increments of 500. The x-axis is labeled as days. The data is as follows. Day 0: number of rotifers alone and number of rotifers with water fleas, 0. Day 2: number of rotifers alone and number of rotifers with water fleas, 0. Day 4: number of rotifers alone and number of rotifers with water fleas, 300. Day 6: number of rotifers alone and number of rotifers with water fleas, 500. Day 8: number of rotifers alone and number of rotifers with water fleas, 800. Day 10: number of rotifers alone, 1700 and number of rotifers with water fleas, 1600. Day 12: number of rotifers alone, 3000 and number of rotifers with water fleas, 1500. Day 14: number of rotifers alone, 4000 and number of rotifers with water fleas, 1100. Day 16: number of rotifers alone, 4200 and number of rotifers with water fleas, 200. Day 18: number of rotifers alone, 4200 and number of rotifers with water fleas, 0.

Analyze the graph and identify some factors that may contribute to the rotifer population leveling off in the absence of water fleas. Explain your answer in 1–2 sentences.

Answer 1

The graph shows that the rotifer population increased when water fleas were present, but leveled off when they were absent. This suggests that water fleas may be a food source for rotifers, and without them, the rotifer population cannot continue to grow.