In the process some of the mass of the hydrogen atoms is converted into energy in the form of light. The same process occurs in thermonuclear (fusion) bombs. In the Sun the process occurs in a controled manner. In a bomb it happens all at once in a big chain-reaction explosion.
Phloem. Definition. noun. A tissue in a vascular plant that functions primarily in transporting organic food materials (e.g. sucrose) from the photosynthetic organ (leaf) to all the parts of the plant.
Xylem is a tubular structure which is responsible for water transport from the roots towards all of the parts of the plant. Phloem is also a tubular structure but is responsible for the transportation of food and other nutrients needed by plant. Xylem imports water and minerals while Phloem transports water and food. It is the principal water conducting tissue of vascular plants. 2  Xylem consists of tracheids, vessels, xylem parenchyma and xylem fibres. 3  Also ray parenchyma Also the xylem of softwoods (Gymnospermae) do NOT contain vessels. 4  It is a living complex permanent tissue. 5  Inner phloem is alive.