The period during which the human body undergoes various changes leading to reproductive maturity is called adolescence. It is called as a period of storm and stress in life. The need is to understand it as normal growth and development process.
Living organisms have a limited lifespan. Unless they are not going to form new organism, they will finish. Their continuity of life will be lost. So, fertile organisms form new organism of same kind either by self or by the help of other individual of same species. The process of formation of similar types of organisms by existing organism is called reproduction.
There are two types of reproductions-
(a) Asexual Reproduction – New organism is formed by single parent. It is common in plants and animals.
(b) Sexual Reproduction- New organism is formed by two parents. It is common in plants and animals.