Answer:
A. Enzymes function best at a specific temperature.
Explanation:
One of the factors that determinate the enzyme activity is temperature. Each enzyme has a temperature optimum (the temperature at which its activity is the highest) and it corresponds to the normal body temperature for humans (around 98.6 degrees Fahrenheit or 37 degrees Celsius). Some of them can work on lower temperatures while some of them can increase their activity with the increase in temperature. But, since enzymes are usually proteins, high temperature (above 40 degrees Celsius) might denature them and consequently enzymes lose their activity.