Answer:
Whereas a change in a person may take 10-50 years to manifest itself, changes in the earth can take millions of years to become apparent. Also, humans may experience changes in their personalities as well as in their bodies, while changes in the earth are never psychological.
Sickle-cell disease is common in tropical and sub-tropical regions because being a carrier, carrying a single sickle-cell mutation (sickle cell trait), affords some resistance to malaria.
D sediment lowers oceanic ph
Also the alimentary canal or digestive tract
