Derek hypothesizes that a potted fern in a closed container will stay healthier than the same type of plant on an open windowsill. At the
conclusion of his investigation, Derek finds that his results support his
hypothesis. Which best explains why Derek should repeat the
investigation?

Select one:

1.to prove the investigation is important

2.to be able to start another investigation

3.to make sure the results are valid

4.to learn why the hypothesis is correct