An allele that causes an altered form of hemoglobin occurs in all human populations as a result of mutation. However in populations where malaria is a threat there is a relatively higher percentage of individuals with the allele. Individuals who have one allele for this condition have an increased resistance to malaria. Individuals with two alleles for this condition have significant medical problems and die young. This allele has been found in high numbers in certain populations in West Africa, Southeast Asia and Greece. 1) What process of evolution likely led to the appearance of this allele

relative dating involves things like higher layers are most recent than rocks lower in the sequence. this can be extended to the known sequence of fossils. rocks containing rabbit fossils are later than those containing dinosaur fossils.  

absolute dating methods mainly use radioactive elements that have known rates of decay and produce recognizable products. for example potassium 40 decays to produce argon. once a rock has solidified the argon is trapped. by measuring the argon and potassium0 you can get an accurate number for the age.  

some other methods are good for archaeological ages. dendrochronology involves recognizing the sequence of tree rings. the orientation of magnetized particles in baked clay can be used to date a fire.

hope this .. .

it will increase due to the time span