Why does sickle-cell hemoglobin (hbs) migrate slower than normal hemoglobin (hba) during gel electrophoresis?

The cause a translocation of the amino acid in position of a normal beta globin, transforming glutamic acid into valine. Then the HBs has less charge due to loss of the glutamic acid.Sickle-cell anemia is a hereditary disease make  by hemoglobin S in its homozygous form. 

explanation:

for  example, forests have higher evapotranspiration than other ecosystems,  such  as grasslands, because of their deeper roots and greater leaf area. thus forests have a net moistening effect on the atmosphere and become a moisture source for downwind ecosystems.

answer : haversian

[explanation: -(compact bone is organized as parallel columns, known as haversian systems, which run lengthwise down the axis of long bones. these columns are composed of lamellae, concentric rings of bone, surrounding a central channel, or haversian canal, that contains the nerves, blood vessels, and lymphatic system of the bone)]