All of those are similar to each other because they are all weeds, or in other words they are all different types of grasses.
Considering the choices;
A. blood glucose level and pH
B. amount of light and temperature
C. amount of light and pressure
D.
temperature and pH
Answer;
D.
temperature and pH
The two factors affect an enzyme's operation the most is the temperature and pH.
Explanation;
Enzymes work best at optimum pH and temperature.
At low temperature for example the enzymes are inactivated while at high temperatures enzymes are denatured.
At optimal temperature and pH; the chemical reaction rate is optimal.