Which option is an observation rather than a hypothesis?

Correct answer: The plant is twenty centimetres tall

The direct answer is C: the plant is twenty centimetres tall. An observation is information obtained directly by seeing, measuring, counting, or otherwise recording what happens. Saying that the plant is twenty centimetres tall reports a present measurement; it does not claim why the plant has that height or what will happen next. Option A is a hypothesis because it predicts that increasing light will cause greater plant height, and this can be tested. Option B is also a testable prediction linking higher temperature with faster melting, so it is a hypothesis rather than a direct observation here. Option C is correct because the plant’s height is a measured fact. Option D is another hypothesis because it predicts that less water will make soil dry faster. A hypothesis is a possible explanation or prediction that can be tested by changing one factor and measuring another. Keep observations separate from predictions and explanations. Memory cue: measured or directly seen fact is observation; an if-then prediction is usually a hypothesis.