AP BIOLOGY

Detailed explanation-1: -The concentration of mineral nutrient elements is higher inside the root-hairs than in the surrounding soil because the absorption of mineral elements from the soil involves active transport by the cells.

Detailed explanation-2: -A root hair contains cell sap which has a higher concentration of salts as compared to the soil water. Hence the root hair cells absorb water from the soil by endosmosis.

Detailed explanation-3: -In soil, roots actively take up ions which create a difference between ion concentration in roots and soil. To eliminate this difference, water from soil moves into the root.

Detailed explanation-4: -Calcium is taken up by roots from the soil solution and delivered to the shoot via the xylem. It may traverse the root either through the cytoplasm of cells linked by plasmodesmata (the symplast) or through the spaces between cells (the apoplast).