D. Because experimentation includes a control group. also, independent and dependent variables are part of an experiment they arent a type of research
The correct answer that would answer the given question above would be EXPERIMENTATION. The scientific method uses observation to gather information, and to answer the questions based on the information gathered, this would involve experimentation. This is the testing of the information so that it would given a clear evidence on the answer. Hope this answer helps.
Answer:
The answers you have chosen are/should correct
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Already took that test
It is released into the atmosphere and mixed in with carbon monoxide
