Integumentary system I believe
Thymine has a methyl group and is better suited for the storage property of the DNA molecule as it is far more stable compared to Uracil.
RNA contain Uracil instead of thymine so as to make differentiation of RNA molecule from DNA molecules easier.
Because they will grow really long if you don't
The data you will collect is the blood phenotype.By adding serums that each contains a particular antibody such as anti-A, anti-B, or anti-D ... to see if there's an agglutination with erythrocytes' antigen and the antibodies, proving the presence of the appropriate antigen in the blood.
This will help to confirm the blood grouping if this technique is done in parallel with the plasma test ( of Simonin-Michon).
