It is best to say that the protection to properties offered by sea walls along coasts
a. decreases the present and future risk to human properties
b. increases both the present and future risk to human properties
c. decreases the present but increases the future risk
d. increases the present but decreases the future risk

Answer; A
It is best to say that the protection to properties offered by sea walls along coasts decreases the present and future risk to human properties. 

Explanation;
Seawalls are vertical walls that are constructed on the sea shores to prevent upland erosion and storm surge flooding. They are massive concrete structures emplaced along a stretch of shoreline mostly at urban beaches. These structures decrease the present and future risk to human properties.

The answer to this will be from your lab notes/procedure. it would be best to ask another student who participated in the lab as we do not know what was done, what enzyme or if the temperature is celsius or fahrenheit. if i were to guess though i'd say the rate stopped due to enzyme denturing at high temperature