Final answer:
The greatest increase in surface area for absorption in the root is due to root hairs, which are extensions of the root epidermal cells that increase the surface area and are particularly important for the efficient absorption of water and nutrients. The correct option is B. root hairs
Step-by-step explanation:
The greatest increase in surface area for absorption in the root is due to root hairs. These are cylindrical extensions from the cells on the outside of roots, which greatly enhance the root's ability to absorb water and nutrients. Root hairs accomplish this by not only increasing the surface area available for absorption but also by improving contact between the soil and the root, thus preventing air spaces that would reduce absorption efficiency. They can extend several millimeters into the soil and significantly impact the water and nutrient dynamics in the root zone.
Root hairs perform multiple functions, making them critical for the absorption of water and minerals. This includes increasing the volume of soil that is within close proximity to the root and actively facilitating nutrient absorption through processes like active transport, thereby making the root hair one of the most important structures in a plant's root system. The correct option is B. root hairs