Whats the best work out to tone my body ,,i weight about 83.lb and i m 5.1Ft and i want to tone it up ,i m 31?

Swimming is the best and easiest way to get a full body work out with as little thought as possible. Just make sure you swim a variety of strokes. I'd suggest you do 15 minutes of roke and 15 minutes of front crawl in the one 30 minute swim. Do this two or three times a week, and then after a week or two increase it to 20 minutes in each stroke - and this will get you toned and keep you toned. You can add variety by making every 4th length a 'sprint' and this will give you a good burn and shape you up nicely. You never see a swimmer with a bad body - good luck.