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 and phloem are the two types of vascular tissues that are present in plants. They are responsible for transporting water, minerals, food and other organic materials between the roots, stems and leaves of the plant.ylem cells are hard walled cells, which are stacked on top of each other and are mainly found in the center of the stem. Hence, xylem has another function, which is to provide mechanical support to the plant. Xylem is surrounded by the phloem. Phloem is the other type of transport tissue in vascular plants.