The diagram illustrates how a frog grows during its lifespan.
Overall, the whole process comprises eight stages, commencing with the reproduction of frog’s eggs and ending with the appearance of mature frogs.
In the initial stages, an adult frog lays several eggs, with the black core of the eggs being the embryo. These eggs are subsequently hatched into tadpoles, clinging to water plants. For breathing purposes, these tadpoles evolved the external gills, accompanied by the continuous growth of tails.
In the fifth stage, the previous developmental form witnessed the appearance of hind legs, and the tail now acted as a food-container, which is the main nutrition source for them. Following this is the appearance of a couple of front legs while their tail becomes shorter. Their tails then vanished gradually, and they are now termed young frogs. Finally, these frogs grow into mature frogs, mating with other frogs to start the life chain again.