Scientists believe earth is about how many billion years old?
a.
3 billion years
b.
4.5 billion years
c.
6 billion years
d.
7.5 billion years

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