Final answer:
The assumption that scientific knowledge is fixed and unchanging is not accurate because scientific knowledge is constantly evolving as new discoveries and evidence emerge(option c).
Step-by-step explanation:
The assumption that is not made by scientists about their work is c) Scientific knowledge is fixed and unchanging.
Scientific research is based on the understanding that the universe operates according to fundamental laws (a) and that these laws are understandable and predictable (b). Additionally, scientists recognize that events in the natural world have natural causes (d). However, the assumption that scientific knowledge is fixed and unchanging is not accurate because scientific knowledge is constantly evolving as new discoveries and evidence emerge.