When heat is added to a substance, the molecules and atoms vibrate faster. Solids, liquids and gases all expand when heat is added. When heat leaves all substances, the molecules vibrate slower. The atoms can get closer which results in the matter contracting.
The causitive agent of the cohesion-tension model of xylem transport is transpiration. During the process of transpiration, water vapor is lost from the stomata of the leaf. To replace this water, water from adjacent cells is withdrawn. The water molecules stick together due to cohesion and are transported upwards through the stem in the form of a stream.<span />
The answers lysosomes, they digest enzymes that break down waste material and the priests in the cell.
