How was the theory of plate tectonics developed? fst!

It was developed by Alfred Wegener around 1912-1915 time frame. He proposed his theory of the "continental drift". He proposed that the continents plowed through crust  of ocean basins. He said that the continents look like a puzzle piece to put together. It's very interesting.

Hope this helped :)

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answer: 21

step-by-step explanation:

divide 630 by 30. 30 goes into 630 21 times