Answer:
c. Observational studies have both independent and dependent variables.
d. Observational studies can be used to test hypothesis.
Explanation:
Observational studies are ones in which a researcher makes observations about his thoughts and views. He observes the risk and other effects before actual test takes place. This is usually the initial phase of research where observations are made for suitability of certain things that are to be researched. There is initial feasibility test conducted to identify whether the further research process is beneficial or not.
The answer to your question is: True. The ancient egyptiants participated in sports such as wrestling, long jump, swimming, rowing, etc
The answer should be limited government
D) operating your vehicle in a manner that optimizes the safety for both yourself and those around you.