Answer: Descriptive, Comparative and Experimental (which comes from experimentation).
Step-by-step explanation:
There are three types of scientific investigations:
- Descriptive: This type of scientific investigation studies parts of a system, which can be natural or artificial. It describes everything that is being studied and no predictions are made. There are three types of descriptive methods: case-study methods (an in-depth study is produced from many sources with different methods), observational methods (no questions asked, just an observation of the behavior of a subject and no manipulation of the variables), and survey method (some people are interviewed and the researchers study the answers.)
- Comparative: It gathers information from organisms, systems, places or from any source, to compare them using also a control group. But, there is no imposed treatment because it is not ethical or because it is not possible. So, the treatment is only observed.
- Experiment: As its names says, it uses an experimental test designed to study some phenomena, where variables are controlled so the treatment is not only observed as the comparative method. Then those variables are measured to collect information or evidence that supports or not a previous hypothesis and is used to assess theoretical knowledge. The independent variable is manipulated while the dependent variable is measured. This type of scientific investigation comes from experimentation.