The sperm and Ovum plays an important role in fertilization. Production of sperm starts only after the puberty in males. Production of Ovum may start after birth, but ova Will be matured after puberty.
Mitosis and Meiosis are the two phases of the nuclear cell division. There are four phases in mitosis, four phases in meiosis-1 and another four phases in meiosis-2 which results in the successful cell division.
The Pheromones and Hormones are the chemical substances which are totally different in their functions. The pheromones act outside of the body of the animal or insect secreting it. The hormones act inside of the body of the animal or human being secreting it.