Choose the correct statement.
A. Nitrogen is transported in plant xylem mainly in organic form
B. P and S carried mainly in organic compounds in plants
C. There is no exchange of material between xylem and phloem
D. Xylem transport only inorganic nutrients

Hint: The xylem present in the plant have four components that are tracheid, vessels, xylem fibres and xylem parenchyma. The function of xylem is to conduct water and minerals. They also provide strength and mechanical support to the plant.

Complete answer:
Plants have their own systems. They have the xylem which moves water and solutes from the roots to the leaves, and the Phloem which moves glucose, made in the leaves by photosynthesis, and amino acids to the rest of the plant.

The process starts in the soil, where nitrogen is found in a number of forms including as organic nitrogen, which comes from living things ammonium, nitrate and nitrite. So when things die and decompose, organic nitrogen is converted into ammonium by the process of mineralization, which is done by a number of bacterial and fungal organisms, and ammonium is converted first to nitrite and then to nitrate through the process of nitrification which is done by bacteria.

Nitrogen (N) is the most essential nutrient for plant growth and productivity. Uptake of organic or inorganic nitrogen from the soil, and transport of the newly synthesized organic nitrogen from the source organs like leaves and roots to sinks (developing leaves, flowers and seeds) are integral to the physiology of plants and very important for the development of the plant.

So, we can say that the plants absorb the nitrogen in the form of nitrate and ammonium.
Hence, the correct answer is option (A).

Note: The xylem and the phloem are found in groups called vascular bundles. And the position of these bundles changes for different parts of the plant. Both the xylem and the phloem are made up of rows of cells that form a continuous tube, running the whole length of the plant. The xylem vessels are made of elongated dead cells that are impermeable to water and have walls containing lignin (a woody material). Because of this, xylem vessels are tough in nature.