2) The diagram below represents a change in guard cells that open and close pores in a plant. Guard cell Open pore Closed pore This change directly helps to A) regulate water loss B absorb minerals C) increase heterotrophic nutrition D) reduce seed production​

A) regulate water loss

Explanation:

Guard cells refer to the cells enclosing each stomata. They assist in monitoring the rate of transpiration by closing and opening the stomata. The guard cells possess the tendency to monitor the closing and opening of stomata by changing shape. The shape of the guard cells modifies on the basis of the concentration of potassium ions and water found in the cells themselves.  

The stomatal pores get closed when carbon dioxide is no longer needed for the process of photosynthesis. The guard cells swell when movement of water takes place inside these pores, and thus, the opening of stomatal pores occurs, and as water moves out, the guard cell closes. Thus, guard cells play an essential role in regulating water loss.  

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