Skin-diving  is a new sport today. This sport takes you into a wonderful new world . It is like a visit to the moon! When you are under water, it is easy for you to climb big rocks , because you are no longer heavy . Here, under water, everything is blue and green. During the day ,there is enough light .When fish swim nearby , you can catch them with your hands . When you have tanks   of air on your back, you can stay in keep water for a long time. But you must be careful when you dive in deep water. To catch fish is one of the most interesting parts of this sport. Besides ,there are many other uses of skin-diving. You can clean ships without taking them out of the water. You can also get many things from the deep sea. ,. You can climb big rocks easily under water because   _  .
you are stronger the fish nearby help you you are not as heavy as on the land there is a lot of light