Roots anchor the plant in one of two ways or sometimes by
a combination of two. The first way is by occupying a large volume of shallow soil
around the plant's base with a fibrous root system, one consisting of many thin,
profusely branched roots. Since these kinds of roots grow relatively colse to the
soil surface, they effectively control soil erosion. Grass roots are specially
well suited to this purpose. Fibrous roots capture water as it
begins to percolate into the ground and so must draw their mineral supplies from
the surface soil before the nutrients are leached to lower levels.
Q: The phrase [this purpose] refers to
A combining two root systems
B feeding the plant
C preventing soil erosion
D leaching nutrients
