Tadpoles to Frog!

In the figure below, the life cycle and completion of a tadpole to a frog is indicated.
Generally, tadpoles undergo 10 stages in order to completely grow and develop into frogs.

Figure 1: Metamorphosis Process (source: www.toadrescue.co.uk)

1: Toad Spawn

2-3: Developing ova

4-5: Tadpoles with external gills

6-7: Development of rear limbs

8-9: Development of front limbs

10: Metamorphosis to a toad

Step 1 to 6 are demonstrating first four weeks of a tadpole. Starting from Week 6, it was observed that they started developing body parts first front and eventually in Week 7 back legs. 

However, it was observed that some tadpoles are still younger than others and have not developed to that level yet.

 Figure 2: Tadpoles

As it can be seen in Figure 1, some of the tadpoles are developing back legs in 6th week.

 Figure 3: A tadpole with its hind leg developed

Figure 3 is an indication of the development process of tadpoles in Week 7, some of them have been developing both front and back legs.

Figures 4 & 5: Tadpole with front and back legs and already shaping to a frog.

Figures 4 and 5 are demonstrations of a tadpole to frog and the 9th step of development which is developing front limps and entering to 10th step which is becoming a complete frog.

The noticeable development and inspiration form them was the respiration system the have developed. It was observed that at this stage they prefer not to be in water all the time but rather to breath and getting on top of the water with occasional swimming.

Tadpoles absorbs oxygen through the water passing their mouth and pass the carbon dioxide through their gills. However frogs are exchanging these gases through their skin.