Answer:
Uracil
Explanation:
DNA only uses Thymine so that leaves Uracil for RNA because all of the other bases are used for both.
The circulatory helps keep you healthy because it delivers nutrients and oxygen to all of your cells(which your cells need)(and you need cells to survive).
The circulatory assists your cells and gives them what they need to stay healthy and keep you alive
Genetic modifications tamper with what would be normal genetics. Genetic modifications are upgrades in genetics whereas genetic sexual reproduction happens by normal means.
I don’t know how to explain it but this might help
