Two students are comparing scientific experiments to investigations. they came up with the following ideas. student a: testing plant growth in different types of soils student b: comparing the water level in a lake during different times of the year which student gave an example of a scientific experiment? a. student a because it requires experimental and control groups b. student b because it requires a hypothesis c. student a because it is preferably done in natural settings d. student b because it is preferably done across a long period of time