Yes / no, is the following a verifiable fact?\n"Plumbing requires extensive knowledge and training in the field to understand what part isn't working and how to fix it."
Step-by-step reasoning:
yes
Plumbing covers everything from toilet pipes to sewer lines, so workers must know a lot about each part and how to fix things.

An every day person would not be able to simply walk up and be able to do what they do.

.

Final answer: yes