The codon is found on the messenger RNA molecule and is complementary to the anticodon on the transfer RNA molecule. The base pairing in RNA molecules is:
Adenine with Uracil (because RNA molecules do not have Thymine) Cytosine with Guanine
This means that the first nucleotide on the anticodon will be uracil.
The very primitive organism is the oldest because, over time, organisms gradually evolved into more complex organisms. First came the primitive organism, then it evolved into the more complex one, or the younger fossil.
