Use Retin-A exactly as your doctor has prescribed it for you. Follow all directions on your prescription label. Do not use this medicine in larger or smaller amounts or for longer than recommended. Do not take by mouth. Retin-A is for use only on the skin.
Definition of wall for English Language Learners : a structure of brick, stone, etc., that surrounds an area or separates one area from another : the structure that forms the side of a room or building
What is Dam. Definition of Dam is as an obstruction constructed across a stream or river. At the back of this barrier water is collected forming a pool. The side on which water is collected is called upstream side and the other side of the barrier is called downstream side. The pool of water which is formed upstream is called a Reservoir.