Sickle-cell anemia is caused by a mutation in the beta globin gene that causes a GAG (glutamic acid) codon to change to a GUG (valine) codon in the messenger RNA. What type of mutation has occurred in the gene

an active site is a region that is present on an enzyme where the reactants or the substrate molecules we can say bind and experience a chemical reaction. the substrate is basically a reactant whose concentration is changing and that is converting into a product after binding at the active site of an enzyme

i'd say that the moon rock is about 2.2 billion years old.