How can tree roots be agents of chemical weathering?

Trees fracture rock with their roots, which makes them easier to break up physically and exposes more surface area for chemical weathering. Bacteria which secrete acid solutions speed chemical weathering.

Plant roots are also an important source of chemical weathering. As roots expand into rock, acids can change the minerals in the rock. Plant roots also use carbon dioxide, thus changing the chemistry of the soil. New, weaker minerals are often more brittle; this makes it easier for plant roots to break up the rock.

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answer; /// i believe that the correct answer is (50%);

equal distribution i think.