horizontal
Left to right
Run
Lines of latitude are horizontal and run parallel to the poles
It is called the slope of a line.
Sprockets are the toothed wheels that the chain run over.
A chain is a chain, it hasn't got any gears in it. But if you run it across a pair of sprockets you can create a gearing ratio.
This would depend on what sprockets you are running and what chain you plan to run. If you don't have a local shop to ask, I would go to this website and ask them: http://www.1trail.com/sa/p/Driven_USA_Suzuki_DZR_400_00-_04_MX_Front_Sprocket.htm
If the bicycle has external gears (several visible sprockets that the chain can run over) then you get the number of "speeds" by multiplying the number of sprockets by the pedals with the number of sprockets at the rear wheel. Most common for a half-decent MTB would be 3x9 = 27 speeds. In reality this isn't entirely true, some of those combos will give the same gear ratios, and some shouldn't be used due to the chain running at an extreme angle. So in practical terms a 27-speed bike will give something like 15-18 usefully different gears.
vertical rise?
It uses a timing chain and sprockets. I don't know how many links are in the chain. It doesn't normally break like a timing belt does, but it does wear out and can cause timing problems. If it is allowed to wear far enough it can jump a tooth and that usually stops the engine from being able to run.
Bicycles have become a bit tricky over the years.There are two different kinds of 18-speeds:One that has three chainrings up front and six sprockets at the rear.(3x6=18),One that has two chainrings up front and 9 sprockets by the rear.(2x9=18)And a chain for a 6-speed rear won't fit on a 9-speed rear, it'll be too wide.You MIGHT be able to run a chain for a 9-speed rear on a 6-speed.Chains are quite cheap, so it doesn't make much sense to get one from ebay.There are two things to think about when getting a new chain:the chain and the sprockets wear together, replacing only one often leads to chain skip and poor shiftingyou've got to get the chain length about right. Too short and you might burst your rear derailer, too long and you can get chain rub on some gears.Chains are usually sold over-long, and needs to be cut to length with a chain breaker tool before being joined back together.
lines of latitude are horizontal lines that form circles and that run in the same direction as the equator
Vertical
run
vertical
Column (Horizontal)