The diagram depicts different life stages of a frog.
Overall, it is a natural, cyclical process involving 7 stages, starting with eggs and finishing with a grown adult frog.
The process starts with tiny eggs being laid in a body of water, which in turn get developed into the embryo. While still confined to its aquatic environment, the embryo develops its legs, which is essential for the next landing step.
As soon as pulmonary breathing accompanies the newly developed legs, the tadpole frog loses its rudimentary tail and begins its new stage of life on the land. After some time, it reaches its final adult form.
