There are some important differences between physical and social sciences: (1) Physical scientists may conduct experiments in order to test and prove hypotheses. In social sciences, the study subjects are human beings and they have the right not to join the test. In addition, creating an environment of a laboratory may hinder people from behaving naturally, thus may be an obstacle to reaching the actual facts. For this reason, social scientists prefer to investigate people in their natural environments rather than in a laboratory environment. (2) In physical sciences, providing that all conditions of the circumstance will be the same, experiments enable scientists to make explicit predictions. However, it is impossible to make predictions with this much certainty in social sciences. The interaction of individuals, groups and society are complex and people may change their minds with their own will, for this reason making estimations in social sciences is not this easy. People may react and behave differently in the same circumstances, they may interpret the same fact differently, or may change their minds. Consequently, the regularities or laws in the social world cannot be put forward with the same certainty degree as in physical sciences. (3) In physical sciences, scientists cannot influence the reaction of their subjects. However, social scientists are members of the society they investigate, they may influence the people they investigate and may be influenced by them. Thus, it is harder to be objective in social sciences than it is in physical sciences. In addition to this, unlike social sciences, physical scientists do not have to persuade the study subjects to cooperate in research. In social sciences, the subjects have free will, the scientists have to persuade the people they investigate to cooperate. People may prefer not to cooperate in research, refuse to answer the questions, or they may give incorrect or deficit information, or may lie intentionally. This kind of behavior would make a sociological research impossible, difficult or unreliable. (4) In physical sciences scientists may investigate facts singly and examine the causality relationship between them. On the contrary, because the structure of the society is complex and there are many factors influencing the causality relations, social scientists have to take the social world as a whole. (5) Measurement is much easier in physical sciences. The subjects of physical sciences are often in measurable conditions, they may be expressed by measures such as weight, length, density or volume. Because there are not standard measures for measuring behaviors, perceptions or attitudes of people, it is harder to make measurements in social sciences. The correct answer is Choice E.