Number 4 is
-Oxidation occurs at the anode, while reduction occurs at the cathode. Recharging a battery involves the conversion of electrical energy to chemical energy. During recharging, there is movement of electrons from an external power source to the anode, and on the other side electrons are removed from the cathode.
Answer:
the citric acid in lemon juice is a natural bleach, or oxidizing agent. It whitens hair by chemically reducing your hair's color pigment, or melanin. When exposed to the sun, the citric acid accelerates the bleaching process
