Topic 3: Lesson 1: Plate Motion

Question 1

an undersea mountain chain where new ocean floor is produced; a divergent plate boundary under the ocean

Answer 1

mid-ocean ridge

Question 2

the process by which molten material adds new oceanic crust to the ocean floor

Answer 2

sea floor spreading

Question 3

the process by which oceanic crust sinks deep beneath a deep-ocean trench and back into the mantle at a convergent plate boundary

Answer 3

subduction

Question 4

an undersea valley that represents one of the deepest part of the ocean

Answer 4

ocean trench

Question 5

rock farther away from a mid-ocean ridge

Answer 5

older

Question 6

rock closer to a mid-ocean ridge

Answer 6

newer

Question 7

drives plate motion

Answer 7

convection currents in the mantle

Question 8

three pieces of evidence that supports the Theory of Continental Drift

Answer 8

fossils, land forms, and climate

Question 9

step one of sea-floor spreading

Answer 9

molten material flows upward through a mid-ocean ridge

Question 10

step two of sea-floor spreading

Answer 10

molten material hardens into strips of rock on either side of the mid-ocean ridge

Question 11

step three of sea-floor spreading

Answer 11

the ocean floor on both sides of the mid-ocean ridge move further away from it

Question 12

step four of sea-floor spreading

Answer 12

the ocean floor widens

Question 13

the Atlantic Ocean has a_____, while the Pacific Ocean has more_____, which causes the Atlantic to widen and the Pacific to shrink

Answer 13

growing mid-ocean ridge–subduction zones