It's irrelevant to the argument, because growing roots isn't learned behaviour. Edit: I feel like I can expand even more on this. Plants grow roots to get wat

It's irrelevant to the argument, because growing roots isn't learned behaviour. Edit: I feel like I can expand even more on this. Plants grow roots to get water is a simplification, roots can serve a lot of purposes. Roots can anchor you so wind doesn't blow you away, and it helps you to extract other nutrients from the ground with their high surface area. It's entirely possible for evolution to cause something like roots to form in an organism because it helps one of these purposes, only for it to become useful for another purpose some time later. The ability for roots to extract water from the ground does not mean that roots were evolved for this specific purpose. Case in point: many kinds of algae have roots and they are literally soaked in water at all times.