Which of these actions is an example of chemical weathering?
a. freezing water widens the cracks in rocks.
b. plant roots force their way into cracks in rocks and break them.
c. oxygen in air reacts with iron content in rocks, causing them to change color.
d. strong winds peel soft rock away, leaving harder rock behind.

the major pests we deal with are insects, weeds and fungal diseases. a pesticide is a product, whether organic or chemical, used to kill the target pest. there are other techniques gardeners should use that can prevent the severe infestations that make the use of pesticides necessary

it forms an anion that has a larger radius. anions have a negative charge and are larger than the original atom.