why pluto is not considered as a planet?
Because of discovery of several objects of similar size in the Kuiper belt.
Pluto
 After 1992, its status as a planet was questioned following the discovery of several objects of similar size in the Kuiper belt. I
nine planets of the solar system in order Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus, Neptune, and Pluto. which are the two segments of this system? Inner planets and outer planets. what is the former one comprises of? The former comprising of the planets  Mercury, Venus, Earth and Mars, is primarily composed of rock and metal. what is the atmospheric condition of the last mentioned planet? There is an atmospheric loss due to trailing off of atmospheric particles. how this planet is named? In English, the planet is named for the Roman god of war, an association made because of its red color, which suggests blood. can you tell me some physical characteristics of this planet? It is approximately half the diameter of Earth, with a surface area only slightly less than the total area of Earth's dry land. what is the time it takes to complete one revolution around the sun? 1 year, 320 days and 18.2 hours. how many  natural satellite it have? Two- Phobos and Deimos. are there any cultural impact related to this planet? In different cultures, Mars represents masculinity and youth. Its symbol, a circle with an arrow pointing out to the upper right, is used as a symbol for the male gender. which are the outer planets of the system mentioned earlier? Jupiter, Saturn, Uranus and Neptune. which among them is the largest? Jupiter and Saturn are the largest among them.
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Pluto [SEP] Introduction
Pluto (minor planet designation: 134340 Pluto) is a dwarf planet in the Kuiper belt, a ring of bodies beyond the orbit of Neptune. It was the first and the largest Kuiper belt object to be discovered. Pluto was discovered by Clyde Tombaugh in 1930 and declared to be the ninth planet from the Sun. After 1992, its status as a planet was questioned following the discovery of several objects of similar size in the Kuiper belt. In 2005, Eris, a dwarf planet in the scattered disc which is 27% more massive than Pluto, was discovered. This led the International Astronomical Union (IAU) to define the term "planet" formally in 2006, during their 26th General Assembly.