Question about mid-altantic ridge

[kingwinner]

1) 5 plates are responsible for the mid-atlantic ridge: N. American, S. American, African, Eurasian, but I can't see where is the 5th one?! (This is the test question I had yesterday but I can't make out the 5th one)

 

2) Is the longest mountain chain on our planet the Andes or the mid-ocean ridge? Lots of sources say the mid-ocean ridge while others say the Andes :doh:

[Turtle]

1) 5 plates are responsible for the mid-atlantic ridge: N. American, S. American, African, Eurasian, but I can't see where is the 5th one?! (This is the test question I had yesterday but I can't make out the 5th one)

 

2) Is the longest mountain chain on our planet the Andes or the mid-ocean ridge? Lots of sources say the mid-ocean ridge while others say the Andes :doh:

 

___1) I think the 5th is the Antartic Plate?

___2) I suggest saying Andes on dry land, Atlantic ridge underwater. There arises a serious problem when measuring boundarys in regard to accuracy, & it is the matter of fractal dimension. As you use a shorter rule (say a yardstick instead of a mile-stick) the length of the boundary increases. Also, the term "largest" is a bit ambiguous; largest in what regard? Highest? Longest? Most volume? Largest footprint? Largest surface area? Moreover, when the measurement is taken plays a role as well since these mountain ranges constantly change. If it is a test question, pin down the instructor on what answer they want & then give it. :)

[kingwinner]

1) Why Antarctic plate? Is the bottom part of ocean ridge between S. American and Antarctic plate still part of the mid-Atlantic ridge?

 

2) So on land, Andes is the longest mountain chain, but if including underwater mountains, mid-ocean ridge would be the longest! :doh: