Explain how enzymes are sensitive to their environment

Enzymes are very sensitive to their ph, temperature, and concentrations of both substrate and enzyme. 
Too high or low ph and temperature cause enzymes to unfold, meaning the active site and the substrate don't fit like a key and a lock, therefore the enzyme doesn't function.  The reason is the intra- and intermolecular bonds that hold the enzymes proteins in their secondary and tertiary structures are disrupted by those changes. 

They include lobsters and crabs