Answer: B) calcium nitrate
To work this out you do 400÷20=20
Weathering because Weathering<span> is the process where </span>rock<span> is dissolved, worn away or </span>broken down into smaller<span> and </span>smaller<span> pieces. There are </span>mechanical<span>, chemical and organic </span>weathering<span>processes. Organic </span>weathering<span> happens when plants </span>break<span> up </span>rocks<span> with their growing roots or plant acids help dissolve </span>rock<span>.</span>