If anyone could explain which block in the periodic table has metals with changing oxidation numbers and why, it would be greatly appreciated

Answer:
D-block
Explanation:
Transition metals are metals of the d-block elements located between group 2 and 3 in the periodic table. They are called d-block element because the filling of electrons in their electronic configuration ends in the d-orbital.
Now, they have variable oxidation state because of their partially filled 3d orbital i.e the 3d orbital is not completely filled.