I am going into 7th grade in 2 weeks...and I am not sure if we do but l think we climb a rope with tiny knots in it but its only like a string 5 times smaller then the rope and its tide tightly around to rope..(just to have a little grip on it) but l cant climb ropes...i climbed the rock wall...i climbed up a rope ladder to get on the swinging log(long story) but l cant climb a rope l swear l have no upper body strength...what exercises should l do to be able to climb the rope...i do not wanna embarrass myself.

Chin ups.

but buddy, do not worry about it, guarantee half your class would not be able to fully complete this task if you were to do it lol, hence why you try new activities with each grade you progress in.

yeah lots of chin ups would help!

The idea behind climbing a rope is similar to climbing a rock wall. Legs and feet. Sure upper bodystrength is great, but if you can develop the technique of using your feet then your hands begin being used for balance.
See the following link: http://wikihow.com/Climb-a-Rope

Those ''tiny knots'' you are talking about are ''lashings'' - a smaller piece of rope is lashed around the large rope. Regardless of how small it is, it will still help your legs propel you up the rope. Use your legs to pinch the rope, your feet to grip the lashings as you ''inch worm'' up the rope. Every puund of weight you can take off of your hands with your legs will make it that much easier to climb.

Good Luck