The human population is closest to . *

1.) 8 million
2.) 7 billion
3.) 7 million
4.) 8 billion

4) 8 billion

Explanation:

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