What might occur if an environment changes suddenly

Mass Extinction might occur if an environment changes suddenly.

Explanation:

An extinction event reflects a broad and accelerated reduction in Earth's biodiversity. Such an occurrence is characterized by a significant shift in multicellular species diversity and availability. It happens as the extinction rate hikes about the speciation rate. Since much of the Earth's diversity and biomass is microbial and therefore hard to quantify, reported extinction events impact the biosphere's readily detected, biologically complex portion instead of the total diversity and richness of existence. These all variations results from environmental changes like temperature, pressure, habitat changing, etc.

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