Transport in Plants Test 8

Main function of lenticels is gaseous exchange.
Lenticel is a pore found in the epidermis of leaves,stem and other organs that are used to control gas exchange. It provides a way for the exchange of gases like carbon dioxide, oxygen and water vapour with the atmosphere through the bark, which is otherwise impermeable to gases. 

Leaf is the main source of food so organic food is transport by leaf to all other part of plant but vein act as the carrier to collect all the food stuff and pass it on ,the transport of water and mineral are also got to the leaf as it is the last portion for water transport as water don't move backward, veins provide a mechanical support to the leaf cells thus act as a piece which had clustered all the leaf cell.

Plants obtain carbon and most of their oxygen from CO₂ present in the atmosphere. The other nutritional requirements are obtained from the minerals and water present in the soil.

1. The minerals are mainly absorbed by the roots which are in direct contact with the soil solution.

2. The absorption of minerals occurs over the entire surface of the young root by the cells of the epiblema.

3. During absorption, the ions or molecules penetrate the inner surface of the living cells or tissues from the surrounding medium through a selective membrane. 

When a plant undergoes senescence, mineral ions are frequently mobilized from older parts to apical and lateral meristems, young leaves, developing fruits and seeds by diffusion and by active uptake by cells in the growing regions. This is known as translocation of nutrients.

So, the correct answer is option C.