What are the types of fertilizers?

Internal fertilization and external fertilizationinternal means When the fusion of the male and female gamete occurs within the female genital tract it is called internal fertilization. This type of fertilization occurs in all terrestrial animals both oviparous and viviparous. Reptiles, Birds and mammals show internal fertilization

external fertilizationThe fusiri of the gametes occurs outside the body of the animal and is common in aquatic animals. In bony fishes, frogs, echinoderms the sperms and ova are released into the water and their union occurs by Chromosome number of few chance. Since fertilization occurs outside the body of the animal externally, this method is called external fertilization.