Insulin causes
a) a decrease in the concentration of blood glucose.
b) a decrease in the permeability of cell membranes to glucose.
c) an increase in the production of glucose from glycogen.
d) an increase in the concentration of blood glucose.
e) none of the above.

Secretion of glucagon causes  an increase in the concentration of blood glucose

Secretion of a decrease in the concentration of blood glucose.

Explanation:

So the answer is A). a decrease in the concentration of blood glucose.

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

the correct option is option d