What is an explanation or an opinion?

An explanation is different than an opinion. An explanation lists information or facts in a clear, understandable way. However, an opinion is a personal comment, observation, idea, judgment, etc., rather than information or fact.

Example, explanation:

The instructor's explanation about why nurses wear sterile gloves during a sterile dressing change was consistent with acceptable nursing standards.

Example, opinion

The nursing instructor's stated opinion was that she felt "acceptable nursing standards" are "unnecessary", despite the fact that nursing standards are set by State laws.