(a) The fusion of male gamete with female gamete is known as fertilization.
(b) The cycle which takes place every month when egg is not fertilized is known as menstruation. It lasts for about two to eight days and during this cycle the lining of uterus slowly breaks and comes out through the vagina as blood and mucus.
©The splitting of nucleus into two daughter cells which can take place in any plane is known as binary fission. It can be seen in Amoeba.
(d)When vegetative part of a plant like the root, stem or leaves develops into new plant under appropriate conditions is known as vegetative propagation.
(e) When body of an organism cuts into any number of pieces and each piece grows into a complete organism. This is known as regeneration. It can be seen in Hydra and Planaria.