right

右 depicts a hand with 口(a mouth) next to it. Since right hand is stronger and more agile among two hands , we use it to do most of our works while the production of food is the most important, so 囗 is added to represent it is our right hand or the right. On the other hand, 又 is the origin of 右. In the past, 又 meant right hand, but after 右 had been invented, 又 solely meant also. Now 右 and 又 share the same pronunciation, it can be seen as an evidence of such evolution.