The answer is C, He developed the concept of interchangeable parts.
Answer:
C. naturalistic observation
Explanation:
Naturalistic observation: This is a research method mostly used by social scientists and psychologists. The techniques include observing the participants in their natural environment. This is a non-experimental, and qualitative research method. The different areas of interest are being recorded and observed by the experimenter or the researcher. The presence of the researcher or the experimenter might be either unknown or known to the participants. Researchers try not to make changes in the environment used for observation, as it can influence the outcome of the study.
Answer:
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