The blood is collected in heparinized capillary tubes to prevent clotting. Heparin is a blood thinner and this anticoagulant is produced naturally by mast cells and basophils. But heparin can not dissolve or break the preformed clots.
No, because it still codes for valine in this case, but if another nucleotide was changed such as GCA it would code for alanine instead.
Genes are what code for those things