medium · Enhanced ACT science
A marine biologist hypothesizes that the density of a specific plankton species is highest in the 'sunlight zone' (0–200 m) and decreases significantly in the 'twilight zone' (200–1,000 m).
| Depth (m) | Plankton Density (count/m^3) |
| :--- | :--- |
| 50 | 1,200 |
| 150 | 1,150 |
| 300 | 200 |
| 600 | 180 |
| 900 | 175 |
Does the evidence support this hypothesis?
- Yes; there is a sharp drop in density once the depth exceeds 200 meters, separating the two zones.
- No; the density is not constant within the sunlight zone, as it drops from 1,200 to 1,150 counts.
- No; the density in the twilight zone is stable, whereas the hypothesis predicted it would reach zero.
- Yes; the hypothesis is supported because the sunlight zone has more available light for the plankton to use.
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