You are presented with the quiz "well-drained soil has a positive impact on a plant 's what growth in that soil" 

But you don't know the answer, so you turn to your teacher to ask for hints. He says that "the looseness of soil has a positive impact on a plant 's roots' growth in that soil" and "pinions tolerate drought and alkaline soil, but prefer loose, well-drained soils". 

So, what's the best answer to the question?


 

        roots   