Answer:
D. Increase in temperature from 20 degrees C to 37 degree C
Step-by-step explanation:
A decrease in substrate concentration might not necessarily lead to an increase in enzymatic activities.
Enzymes are pH specific. Thus increasing the pH of operation from 6.8 to 7.4 might destroy the enzyme.
Reactants need to overcome a minimum energy (activation energy) before they can be converted to products. The higher this energy, the lower the rate of reaction. Hence, increasing in activation energy will lead to a lower rate of enzymatic reaction.
Enzymes work optimally at a temperature that is close to the human's body temperature which is 37.5 degrees. Hence, increasing temperature from 20 degrees to 37 degrees will result in an increased enzymatic activities.
The correct option is D.