Answer:
Growth of the plants
Explanation:
In an experiment a logical set of attributes of an object is changed and the logical set of attributes which is affected by the other attribute change is noted. The set of attributes which are logical are called variables.
There are two types of variables are
The independent variable is the input. The output is observed with respect to the input.
Dependent variables are the output which is the result of the change in the independent variables
Here, the researcher wants to know how talking to plants affects their growth. The input is talking to plants and the output is the growth of the plants.
Hence, the independent variable is the growth of the plants.