Final answer:
In an experiment, the dependent variable is what is being measured and is expected to change as a result of the manipulation of the independent variable. In the context of the study about ten-year-old boys eating doughnuts, 'The weight gained' is the dependent variable.
Step-by-step explanation:
In an experiment, the dependent variable is the variable that is being tested and measured. It is expected to change as a result of alterations to the independent variable. For example, in the study where ten-year-old boys are fed doughnuts every morning for a week and then weighed, the dependent variable is d. The weight gained. This is because the weight gain is what the researchers are measuring and what they expect to change as a result of eating doughnuts.
The independent variable is the variable that is manipulated by the researchers to observe if it causes any changes to the dependent variable. In the doughnut study, the independent variable would be a. The doughnuts, as that is what is being given to the boys to see if it affects their weight.
Distinguishing between independent and dependent variables is crucial for analyzing cause-and-effect relationships in experiments. By manipulating the independent variable, researchers can observe the effects on the dependent variable, which can help to confirm or disprove causation between them.