Experiments allow researchers to: a) reflect the natural environment. b) study the entire complexity and uniqueness of an individual. c) inexpensively adhere to the scientific method. d) determine a cause-and-effect relationship.

d) determine a cause-and-effect relationship.

Explanation:

The experiment is a type of scientific research that aims to obtain the causal relationship (cause and effect) between two variables.

Thus, the researcher manipulates and controls one or more independent variables and observes the variation in the dependent variables.

For example, suppose you suspect that the number of colors available increases the number of phones sold. At first, you analyze the normal selling rate with traditional colors. In a second moment you increase the amount of colors available and compare the new sales rate with the natural rate. If there is a difference, the sales level (dependent variable) was affected by the independent variable (available colors).

all cities have a governor

all cities are in states or provnies then country

all cities have people

difference

some are rich

some are poor

some are average