Etiology. Cerebral palsy is relatively common, affecting 1 in 200 children. This number takes into account the full spectrum of the disorder, including milder cases, a broad definition of age of insult, and more complete case ascertainment.
Chemical weathering is the weakening and subsequent disintegration of rock by chemical reactions. These reactions include oxidation, hydrolysis, and carbonation.These processes either form or destroy minerals, thus altering the nature of the rockâs mineral composition.emperature and, especially, moisture are critical for chemical weathering; chemical weathering of rock minerals generally occurs more quickly in hot, humid climatic regions. Oxidation is the reaction of rock minerals with oxygen, thus changing the mineral composition of the rock.
Oxygen is present in air and water and is an important part of many chemical reactions. One of the more common and visible chemical weathering reactions is the combination of iron and oxygen to form iron oxide (rust). Oxygen reacts with ironâbearing minerals to form the mineral hematite (Fe2O3) , which weathers a rusty brown.