Final answer:
The independent variable in Sabrina's experiment on plant growth influenced by sunlight is 'A. the different light conditions'. This is the variable Sabrina changes to observe its effect on the dependent variable, which is the growth of the plants.
Step-by-step explanation:
In the experiment conducted by Sabrina on how sunlight affects plant growth, the independent variable is the factor that Sabrina is deliberately changing to see what effect it has on plant growth. Since Sabrina has placed plants in different light conditions, the independent variable would be 'A. the different light conditions'.
Independent vs. Dependent Variables
In any scientific experiment, the independent variable is the one that is changed or controlled by the scientist to test its effects on the dependent variable, which is the variable being tested and measured. In the context of Sabrina's experiment, the dependent variable is the growth of the plant, as that is what is being measured in response to the changes in sunlight exposure.
Control variables such as the amount of water, the type of soil, and the amount of carbon dioxide given to each plant also play a crucial role. These must be kept constant to ensure that any differences in plant growth are due to the independent variable alone and not other, uncontrolled factors.