Answer : Explanation : A number of possible explanations for why manhole covers are round include : 1. A round manhole cover cannot fall through its circular opening, whereas a square, rectangular, or oval manhole cover could fall in if it were inserted diagonally in the hole.2. Circular covers don’t need to be rotated or precisely aligned when placing them on the opening.3. A round manhole cover is easily moved and rolled.4. Human beings have a roughly circular cross-section.5. Round tubes are the strongest shape against the compression of the earth around them, so the cover of the tube would naturally be round as well.6. It’s easier to dig a circular hole.
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