Answer:
The independent variable here is the types of soil
Step-by-step explanation:
An independent variable is the variable that is not affected by the outcome of other variables in a given experiment. This variable is the variable that is intentionally altered/changed (directly or indirectly) by the researcher in order/expected to produce a result for the experiment. Thus, the independent variable here is the types of soil. This is because the soil was intentionally changed/varied by the researcher and it's expected to determine the heights of the bean plants grown.