It was observed in a group of tadpoles of a mutant frog reared in a laboratory that their development was arrested at a particular stage. The exact tissue that was affected by the mutation is unknown. The development was then resumed and accelerated by injecting the tadpoles with extracts prepared from various tissues of the wild type frogs.The
observations of the experiment are given below.

From the above observations, find out the tissue that is affected by the mutation.