What changes are seen in starch on adding iodine solution?

Starch-iodide solution is

The acidic solution of a salt produced a deep blue colour with starch iodine solution. The salt may be

In the given figure, the filter paper containing starch soaked in potassium iodide solution is connected to the battery as shown. When we write on the wet paper, it has a blue black colour. (i) Iodine is formed at the anode. (ii) Iodine turns blue black in the presence of starch.

What are the changes seen in girls and boys at the time of puberty?