South Carolina READY 4th Grade Science Practice Test

The choice highlighting that more sunlight will result in taller plants presents a clear cause-and-effect hypothesis. This statement proposes a direct relationship between the amount of sunlight and the height of the plants, making it easy to test through experimentation. By measuring the growth of plants exposed to varying amounts of sunlight, one can gather data to either support or contradict the hypothesis. It encourages a focused investigation that can yield quantifiable results, which is essential in scientific practice. In contrast, the other options do not lend themselves to effective testing in the same way. For instance, stating that all plants need sunlight to grow is more of a general observation rather than a testable hypothesis. Similarly, claiming that plants grow best in dark conditions conflicts with the understanding of plant biology and is not an actionable test. Lastly, suggesting that plants grow at the same rate in all light conditions does not allow for measurable differences, which is key in developing a scientific hypothesis. Thus, the chosen hypothesis stands out for its clarity and testability.