Which revision best makes a scientific question more precise?

Correct answer: Does changing daily hours of light alter plant height in seven days?

The direct answer is C: changing the daily hours of light and measuring plant height after seven days is the most precise question. A strong scientific question identifies what will be changed, what will be measured and often the time period. Here, hours of light are the independent variable, plant height is the dependent variable, and seven days gives a clear observation period. Option C is correct because another investigator could understand and test it. Option A, “Are plants good?”, is vague because “good” has no defined measurement. Option B, “Why do plants grow?”, is very broad and may involve many factors, so it does not state a manageable test. Option D, “Is nature wonderful?”, is a personal or philosophical question and has no clear measurable variables. A precise question should avoid vague words and define the comparison. The wording does not guarantee a particular result; it only makes the investigation testable. Exam cue: look for variable, measured outcome and time limit.