I think for your distilled water of 1 it would look like 27.8 +/- 5 because you can go 5 above or below your average and 2 would be 27.8 +/- 10 because you can go 2 times below or above your average?
The single mutation is in the B subunit of hemoglobin. one point mutation changed one amino acid and in malaria country the resulting trait, sickle cell trait, is very helpful to have in a heterozygous condition.
Hope this help:))
A vein. This is because veins carry deoxygenated blood back to the heart.