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 one of two types of vascular tissues found in plant (the other being Phloem). The word Xylem is derived from the Greek for wood. The xylem is responsible for the transport (translocation) of water and soluble mineral nutrients from the roots throughout the plant, this facilitates the replacement of water lost during transpiration and photosynthesis.