Answer:
Comets are composed of ice, dust and frozen gases. The core of the comet is known as nucleus which is formed of rocks and frozen gases. Coma is the atmosphere of the comet. As the comet enters the inner solar system, the coma expands due to sublimation of frozen gases. As it nears the sun, the coma extends backwards and forms a long tail. It extends backwards due to the solar wind. The charged particles from the sun take away the evaporated material and dust of the comet backwards forming tail.