Which of the following changes to Earth is caused predominantly by living organisms? A. The production of dirt.
B. The release of free nitrogen into the atmosphere.
C. The release of sulfur dioxide into the atmosphere.
D. The movement of air currents by convection cells.

D.the movement of air currents by conversation cells

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