Question

in the experiment the soil, plant species, container size, and water source were kept the same. which vocabulary term does this image represent? inference dependent variable independent variable controlled variable

Explanation:

In the experiment, soil, plant species, container size, and water - source are kept the same. Controlled variables are factors that are held constant in an experiment to ensure that only the independent variable affects the dependent variable. Here, these factors are controlled.

Answer:

D. controlled variable