The grand canyon i believe
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C - North to South
The Mekong, Irrawaddy, and Chao Phraya rivers all flow from North to South, thus answering your question.
Hope this helps!
The PERIMETER of the equator cycle is about 40,000Km. The Greenwich cycle is a bit shorter as the earth is a bit an ellipsoid. About 37,000Km by Google Maps. The distance on the envelope between ANY antipodes (=opposite points on the axis, I won't use "diameter" to avoid confusion) is HALF the perimeter (If you walk the whole perimeter long, you'd get to the same point, of course). The distance through Earth is
D=P/Pi=37,000Km/Pi=about11777Km
The gravity model was created by Newton.