It is well developed and has the alimentary canal and digestive glands. The alimentary canal of the frog is not long, but it is short. The mouth that is present on the head opens into the buccal cavity that has the sticky tongue which is bi-lobed. The mouth opens into the pharynx and oesophagus.
This tube-like oesophagus opens into the stomach. It leads to the intestine and the rectum. The rectum opens through an opening called the cloaca. Liver and gallbladder organs are also present along with the pancreas. The liver secretes bile and the pancreas secrete the pancreatic juices.
The food is broken down into simpler substances and in the intestine, it is absorbed and assimilated. Any undigested food waste goes into the rectum and is passed out through the cloaca.
For the leaves to be presearved as fossil, they have to undergo a natural process of carbonization. This involves a slow chemical reaction with water over time that allows oxygen, nitrogen, and hydrogen to escape the leaves’ structure as gases leaving behind a carbon skeleton/film.