To determine the flask's carrying capacity for rotifers in the presence of water fleas, we need to look for the maximum number of rotifers present when water fleas are also present.
From the data provided, the number of rotifers with water fleas is:
- Day 0: 0
- Day 2: 0
- Day 4: 300
- Day 6: 500
- Day 8: 800
- Day 10: 1600
- Day 12: 1500
- Day 14: 1100
- Day 16: 200
- Day 18: 0
The peak number of rotifers with water fleas is observed on Day 10, where there are 1600 rotifers.
Thus, the carrying capacity for rotifers in the presence of water fleas is 1,600.
However, since this number isn't in the multiple-choice options provided, it appears there may have been a misunderstanding or a mistake in the answer options provided. If we are confined to the given options and must select one, we would have to acknowledge that none accurately reflect the carrying capacity derived from the data when water fleas are involved.
Nevertheless, based on the data, the capacity from the highest reading is 1,600.