Are all people under one zodiac sign the same?

It is not possible that the whole world has only 12 types of people. There are innumerable factors for different human traits and hence there are many clues given by different planets posited in different signs. The sum of all these factors, properly balanced, gives the characteristics of the person.

No they are not. There is more to astrology than just the Sun signs. There are also other planetary signs, angles, houses and aspects. They vary according to the date, place and time a person was born.