Q.african violet
My African violets have grown quite tall (long?). The stem is too long and not attractive. If I cut it off to be shorter, will it root again?

This can happen with older African Violets just due to their age. They also can get leggy if they are 'reaching' for the light. Rotating the plant can help maintain a more upright growth pattern.
Propagation is quite easy. Leaf cuttings can be easily potted to start new plants.
Here is a link with more information.
https://www.gardeningknowhow.com/houseplants/african-violet/tips-for-easy-african-violet-propagation.htm
https://www.gardeningknowhow.com/houseplants/african-violet/african-violet-care.htm