Since the main objective of this experiment is to determine the effect of porosity on seedling growth that should be the only independent variable. In short, that is the only variable that should be different to ensure fair testing.
The answer should be B:
he plants seedlings in soils with different levels of porosity and equal levels of permeability.
Permeability is not what needs to be tested. If it changes, you may not be able to determine whether it was the porosity or permeability that cause changes.
Answer: how to draw a circle
Explanation:
There must be a conducting wire and electromotive force or free electrons
How do you mean? I mean, physic professors teach physics...