D. rift valleys.
Trenches occur at convergent oceanic plates; fossils are extremely old bones, bodies, or footprints, which have gotten so old the intervening years have turned them into rock; U-shaped valleys are valleys which are shaped like the letter U, and are usually formed by glaciers, which tend not to occur underwater very often.
Answer:
Physical weathering enhances the rate of chemical weathering .
Explanation:
Physical weathering is the breaking down of rocks by various processes like freezing and thawing without altering the rocks chemical composition.
While, chemical weathering involves the disintegration and dissolution of rocks by the chemical processes like oxidation , carbonation and solution processes etc.
Generally a fractured rock can easily be weathered by chemical agents rather than a normal fractured rock.
So ,
when a rock is already subjected to physical weathering, the rock will develop cracks on it and when the chemical agents comes in contact with that rock, the chemical solution will penetrate into those cracks and will dissolve the rocks at a rapid rate.
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