How do the meanings of the words exercise and fitness differ?

Since there are no choices, I will just answer them based on a personal trainer's perspective. Muscles are best warmed up before stretching because they are already contracted and relaxed making movement in the joints more fluid. If an exercising individual performs a stretch when the muscles are cold, injuries are likely to happen. This is because the muscles are too cold and unprepared for the demanded movement. 

However, the on-going trend in the fitness industry these days is to know what are the two types of stretching activities. These are the active and passive stretches. Active stretch is best done BEFORE a work-out; this involves active movement of the joints and the whole body while performing a light stretch. Passive stretch is best done AFTER a work-out; this lessens the lactic build-up that occurs in the muscles after a physical activity.