Bikes (bicycles)?

Ok ok, I admit it, I really don't know much about bikes other than riding them lol. But one question! On some bicycles (im using that term not to confuse some of ya) there are these things at the end of the handle bars (one per each handlebar) the stick out like this: / or \ And this is at the and of the handles and it looks like a security to keep you hand from going off the handle.... Acctually.... only some bikes have them... im not talking about racing bikes but... ok im getting confused of wat im typing so tell me what they are called why they are there please

Your description sounds like bar ends.

On bicycles with straight handlebars such as mountain bikes and hybrid bikes, one can add bar ends. Those bar ends allow you to change your hand position to prevent hand fatigue.

Yeah, they're called Bar Ends. They do two things. Mostly, they offer the rider opportunity to change hand positions so they can reduce cramping, fatigue, etc. or lower their body so they can be more "streamlined" (not usually an issue on a mountain bike.
The second, and much less important thing they do is protect the hands of the mountain bike rider when going through brush filled trails. They don't do a very good job of this though and you're better off getting a good pair of gloves.

They are called bar ends. Bar ends are available in a number of sizes and shapes. There are a number of reasons to get them on a flat bar bike, such as a mountain bike or hybrid. The most common reason is to give the rider a variety of hand positions so his hands don't get numb. Road bikes with drop "ram's horn" handlebars already offer a variety of hand positions so they don't need bar ends.

HTH

these are bar ends. they give you (as stated) other options for hand positions on a flat bar MTB, but also, they provide additional leverage for lifting your front end over obstacles when climbing! they are less common on MTBs with riser bars, as the risers give you some of the leverage.

throttle