The main difference between meiosis i and meiosis ii is that in meiosis ii

There are many differences between meiosis I and meiosis II but the main difference is that genetic recombination occurs in meiosis I but not in meiosis II.

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