AP BIOLOGY

Detailed explanation-1: -The two primary vascular tissues are xylem, which transports water and dissolved minerals from the roots to the leaves, and phloem, which conducts food from the leaves to all parts of the plant.

Detailed explanation-2: -The major driving force for transport of water through xylem in plants during the day is transpiration which creates transpiration pull and during the night is root pressure due to the absence of transpiration.

Detailed explanation-3: -Xylem is responsible for the transport of water and dissolved ions from the roots upwards through the plant.

Detailed explanation-4: -Water from the soil is absorbed by the roots through a process known as osmosis. The cell membrane of the root hair cells acts as a semi-permeable membrane. The cell sap inside the vacuole is a strong solution with low water concentration.

Detailed explanation-5: -Plants absorb water through their entire surface – roots, stems and leaves. However, the majority of water is absorbed by root hairs. Root hairs are thin-walled uni-cellular outgrowths of epidermis.