AP BIOLOGY

Detailed explanation-1: -Stems support the whole plant and help it to stand erect. It also helps in the transportation of food and water. At the same time, the function of leaves is to prepare food by the process called photosynthesis. Thus, it is not the leaf but it is the stem that holds the plant upright.

Detailed explanation-2: -Stems are one of the three organs of a plant. The primary function (most important job) of a stem is mechanical support. Mechanical support means the plant’s stem supports the plant and holds it upright to help it grow toward sunlight. Stems also connect the other organs of the plant.

Detailed explanation-3: -Stems hold plants upright, bear leaves and other structures, and transport fluids between roots and leaves. Like roots, stems contain dermal, ground, and vascular tissues. Trees have woody stems covered with bark.

Detailed explanation-4: -Parenchyma cells, which make up the bulk of the stem, are thin walled with large vacuoles. In leaves and stems of seedlings and small plants it is the water content of these cells that holds the plant erect.