How can convection in the mantle affect the positions of Earth's continents?

Scientists believe that convection circulation within the mantle helps continents to move. As heat from Earth's innermost layer—the core—transfers to the bottom layer of mantle rock, the rock warms, softens, and rises upward. ... This churning motion in the mantle appears to be a major factor in plate movement.

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the answer is:  

line graphs show patterns in data with variables that change over time; whereas, circle graphs show data as parts out of a whole (such as out of 100%).

answer: they produce more slow than unicellular organisms.