In Response to Drying Soils

In response to drying soils:

A) elongation in roots is suppressed, leading to thick and tougher roots better able to pull water from the soil.
B) elongation in roots is promoted, allowing roots to extend deeper into potentially wetter soil layers.
C) cell division in roots accelerates, allowing roots to extend deeper into potentially wetter soil layers.
D) older root xylem walls thicken to resist the higher tensions needed to pull water from the soil.