The Atlantic Ridge has mountains and deep valleys in the hemispheres, north and south.
The East Pacific Rise has no large mountains or valleys because the Pacific Rises oceanic crust is moving away from the east.
After the rise of Islam in the Hejaz, Arab culture and language were spread outside the Arabian Peninsula through conquest, trade and intermarriages between members of the non-Arab local population and the peninsular Arabs. The Arabic language began to serve as a lingua franca in these areas and dialects were formed.
The answer is steamboats! The first steamboat came year 1807 and was invented by John Fitch:)
