heat definition In physics, a form of energy associated with the movement of atoms and molecules in any material. The higher the temperature of a material, the faster the atoms are moving, and hence the greater the amount of energy present as heat.
Cilia (singular: cilium) are microscopic, hair-like structures that extend outwardfrom the surface of manyanimal cells. These structures are important in the cell cycle and replication, and cilia play a vital part in human and animal development and in everyday life. A typical cilium is between one and ten micrometers long, and usually less than one micrometer wide.
what are cilia and flagella? Cilia and flagella are whip-like appendages of many living cells that are used to move fluid or to propel the cells. Cilia beat with an oar-like motion and flagella have a snake-like motion as illustrated in Figure 1. The cilia in your lungs keep dirt and dust from clogging your breathing tubes (the bronchi) by moving a layer of sticky mucous along to clean out the airways. Sperm cells use a flagellum as a propeller to move the cell through the fluid of the oviduct to reach the egg. Thousands of animals and plants use cilia and flagella for swimming (example: paramecium), or feeding (example: clams and mussels) or mating (example: green algae).