Explanation:

According to the law of conservation of electric charge, the wool must have a positive charge. The electrization, by any method that is carried out, is a transfer of electrons between the bodies involved in the process. All the electrically neutral bodies have the same amount of negative charges (electrons) and positive charges (protons).

When the wool and the rubber are rubbed, a certain amount of electrons passes from the wool to the rubber, so the rod acquires an excess of charge negative. In the same way, the wool will have uncompensated protons, which give the wool a positive charge.